U.S. patent number 11,432,333 [Application Number 16/773,825] was granted by the patent office on 2022-08-30 for techniques for using multiple sets of uplink resources in a random access procedure.
This patent grant is currently assigned to QUALCOMM Incorporated. The grantee listed for this patent is QUALCOMM Incorporated. Invention is credited to Vinay Chande, Arumugam Chendamarai Kannan, Makesh Pravin John Wilson, Tao Luo, Ozcan Ozturk, Jing Sun, Xiaoxia Zhang.
United States Patent |
11,432,333 |
Chande , et al. |
August 30, 2022 |
Techniques for using multiple sets of uplink resources in a random
access procedure
Abstract
A user equipment (UE) may transmit a random access request
message to a base station in a random access procedure to access a
wireless network. In response, the base station may transmit a
random access response message to the UE including an uplink grant
for a first set of uplink resources for the UE to transmit a radio
resource control (RRC) message. The UE may determine a second set
of uplink resources for transmitting the RRC message, for example,
based on additional uplink grants received in the random access
response message. Additionally or alternatively, the UE may derive
additional grants implicitly from the first uplink grant received
from the base station. The UE may transmit the RRC message to the
base station using the first and/or second sets of uplink resources
and establish a connection based on the RRC message for subsequent
uplink and downlink communications.
Inventors: |
Chande; Vinay (San Diego,
CA), Zhang; Xiaoxia (San Diego, CA), Luo; Tao (San
Diego, CA), Chendamarai Kannan; Arumugam (San Diego, CA),
Sun; Jing (San Diego, CA), John Wilson; Makesh Pravin
(San Diego, CA), Ozturk; Ozcan (San Diego, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Assignee: |
QUALCOMM Incorporated (San
Diego, CA)
|
Family
ID: |
1000006530303 |
Appl.
No.: |
16/773,825 |
Filed: |
January 27, 2020 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20200245371 A1 |
Jul 30, 2020 |
|
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
62797645 |
Jan 28, 2019 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W
72/14 (20130101); H04W 72/1278 (20130101); H04W
74/0833 (20130101); H04W 72/04 (20130101); H04W
76/10 (20180201) |
Current International
Class: |
H04W
74/08 (20090101); H04W 72/12 (20090101); H04W
72/14 (20090101); H04W 72/04 (20090101); H04W
76/10 (20180101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
WO-2019018799 |
|
Jan 2019 |
|
WO |
|
Other References
International Search Report and Written
Opinion--PCT/US2020/015483--ISA/EPO--dated Apr. 8, 2020. cited by
applicant .
LG Electronics Inc: "Enhanced RACH Procedure for NR-U", 3GPP Draft,
3GPP TSG-RAN WG2 #104, R2-1818100 Enhanced RACH Procedure for NR-U,
3rd Generation Partnership Project (3GPP), Mobile Competence
Centre, 650, Route Des Lucioles, F-06921 Sophia-Antipolis Cedex,
France, vol. RAN WG2, No. Spokane, USA, Nov. 12, 2018-Nov. 16,
2018, Nov. 12, 2018 (Nov. 12, 2018), XP051557606, 4 Pages,
Retrieved from the Internet: URL:
http://www.3gpp.org/ftp/Meetings%5F3GPP%5FSYNC/RAN2/Docs/R2%2D1818100%2Ez-
ip, [retrieved on Nov. 12, 2018], the whole document. cited by
applicant .
VIVO: "Enhance RACH with Additional Transmission Opportunities",
3GPP Draft, 3GPP TSG-RAN WG2 Meeting #104, R2-1818258 Enhance RACH
with Additional Transmission Opportunities, 3rd Generation
Partnership Project (3GPP), Mobile Competence Centre, 650, Route
Des Lucioles , F-06921 Sophia-Antipolis, vol. RAN WG2, No. Spokane,
USA, Nov. 12, 2018-Nov. 16, 2018, Nov. 12, 2018 (Nov. 12, 2018),
XP051557759, 6 Pages, Retrieved from the Internet: URL:
http://www.3gpp.org/ftp/Meetings%5F3GPP%5FSYNC/RAN2/Docs/R2%2D1818258%2Ez-
ip, [retrieved on Nov. 12, 2018], the whole document. cited by
applicant.
|
Primary Examiner: Jain; Raj
Attorney, Agent or Firm: Do; Liem T.
Parent Case Text
CROSS REFERENCE
The present Application for Patent claims the benefit of U.S.
Provisional Patent Application No. 62/797,645 by CHANDE et al.,
entitled "TECHNIQUES FOR USING MULTIPLE SETS OF UPLINK RESOURCES IN
A RANDOM ACCESS PROCEDURE," filed Jan. 28, 2019, assigned to the
assignee hereof, and expressly incorporated by reference in its
entirety.
Claims
What is claimed is:
1. A method for wireless communications at a user equipment (UE),
comprising: transmitting a random access request message to a base
station; receiving a random access response message from the base
station in response to the random access request message, the
random access response message comprising a grant for a first set
of uplink resources for transmitting a radio resource control
connection request message to the base station; determining at
least a second set of uplink resources for transmitting the radio
resource control connection request message to the base station
based at least in part on a relationship between the first set of
uplink resources and the second set of uplink resources, and the
grant for the first set of uplink resources; performing a channel
access procedure for both the first set of uplink resources and the
second set of uplink resources; transmitting, based at least in
part on performing the channel access procedure, the radio resource
control connection request message to the base station using one or
more of the first set of uplink resources or the second set of
uplink resources; and establishing a connection with the base
station based at least in part on the radio resource control
connection request message.
2. The method of claim 1, further comprising: receiving timing
information from the base station, the timing information
indicating a time-domain offset between the random access response
message, the one or more of the first set of uplink resources, the
second set of uplink resources, or a combination thereof; and
transmitting the radio resource control connection request message
according to the timing information.
3. The method of claim 1, further comprising: receiving a multiple
grant configuration in a system information block message, a
remaining minimum system information message, a dedicated signaling
message, or a combination thereof.
4. The method of claim 3, further comprising: determining at least
the second set of uplink resources for transmitting the radio
resource control connection request message to the base station
based at least in part on the multiple grant configuration.
5. The method of claim 3, wherein the multiple grant configuration
indicates a maximum number of grants, the relationship between the
first set of uplink resources and the second set of uplink
resources, a modulation and coding scheme, or a combination
thereof.
6. The method of claim 1, further comprising: repeating
transmission of the radio resource control connection request
message to the base station using one or more of the first set of
uplink resources or the second set of uplink resources.
7. The method of claim 6, wherein the random access response
message comprises grant multiplicity information, the grant
multiplicity information indicating a number of grants to be used
for repeating transmission of the radio resource control connection
request message, and wherein repeating transmission of the radio
resource control connection request message to the base station is
based at least in part on the grant multiplicity information.
8. The method of claim 1, wherein the random access response
message comprises one or more additional grants for at least the
second set of uplink resources, and determining at least the second
set of uplink resources is based at least in part on the one or
more additional grants.
9. The method of claim 8, wherein each of the grant and the one or
more additional grants comprises a random access preamble
identifier, or a temporary cell identifier, or both, for
transmitting the radio resource control connection request message,
each random access preamble identifier or each temporary cell
identifier, or both, of each of the grant and the one or more
additional grants having a same value.
10. The method of claim 8, wherein each of the grant and the one or
more additional grants comprises a temporary cell identifier for
transmitting the radio resource control connection request message,
one or more of the temporary cell identifiers of the grant and the
one or more additional grants having different values.
11. The method of claim 1, further comprising: transmitting the
radio resource control connection request message using whichever
of the first set of uplink resources or the second set of uplink
resources has an earliest time component.
12. The method of claim 1, further comprising: transmitting the
radio resource control connection request message using whichever
of the first set of uplink resources or the second set of uplink
resources corresponds to a first successful channel access
procedure.
13. The method of claim 1, wherein each of the grant and one or
more additional grants for at least the second set of uplink
resources comprises respective channel access procedure parameters
for the first set of uplink resources or the second set of uplink
resources, and transmitting the radio resource control connection
request message to the base station is based at least in part on a
successful result of the channel access procedure according to the
respective channel access procedure parameters.
14. The method of claim 13, wherein the channel access procedure
parameters comprise a channel access priority, channel occupancy
time information, or a combination thereof, for the first set of
uplink resources or the second set of uplink resources.
15. The method of claim 1, further comprising: determining a signal
strength associated with each of the first set of uplink resources
and the second set of uplink resources; and transmitting the radio
resource control connection request message using whichever of the
first set of uplink resources or the second set of uplink resources
is associated with a greatest signal strength.
16. A method for wireless communications at a base station,
comprising: receiving a random access request message from a user
equipment (UE); transmitting a random access response message to
the UE in response to the random access request message, the random
access response message comprising a grant for a first set of
uplink resources for receiving a radio resource control connection
request message from the UE; receiving the radio resource control
connection request message from the UE using one or more of the
first set of uplink resources or a second set of uplink resources,
wherein one or both of the first set of uplink resources or the
second set of uplink resources corresponds to a successful channel
access procedure, and wherein the second set of uplink resources is
based at least in part on a relationship between the first set of
uplink resources and the second set of uplink resources, and the
grant for the first set of uplink resources; and establishing a
connection with the UE based at least in part on the radio resource
control connection request message.
17. The method of claim 16, further comprising: transmitting timing
information to the UE, the timing information indicating a
time-domain offset between the random access response message, the
one or more of the first set of uplink resources, the second set of
uplink resources, or a combination thereof; and receiving the radio
resource control connection request message according to the timing
information.
18. The method of claim 16, further comprising: receiving a
repeated transmission of the radio resource control connection
request message from the UE using one or more of the first set of
uplink resources or the second set of uplink resources.
19. The method of claim 18, wherein the repeated transmission of
the radio resource control connection request message to the base
station is based at least in part on grant multiplicity information
included in the random access response message.
20. The method of claim 16, wherein the random access response
message comprises one or more additional grants for the first set
of uplink resources, and the second set of uplink resources are
based at least in part on the one or more additional grants for the
first set of uplink resources.
21. The method of claim 20, wherein each of the grant and the one
or more additional grants comprises a random access preamble
identifier, or a temporary cell identifier, or both, for
transmitting the radio resource control connection request message,
each random access preamble identifier or each temporary cell
identifier, or both, of each of the grant and the one or more
additional grants having a same value.
22. The method of claim 20, wherein each of the grant and the one
or more additional grants comprises a temporary cell identifier for
transmitting the radio resource control connection request message,
one or more of the temporary cell identifiers of the grant and the
one or more additional grants having different values.
23. The method of claim 16, further comprising: receiving the radio
resource control connection request message using whichever of the
first set of uplink resources or the second set of uplink resources
has an earliest time component, using whichever of the first set of
uplink resources or the second set of uplink resources corresponds
to a first successful channel access procedure, using whichever of
the first set of uplink resources or the second set of uplink
resources is associated with a greatest signal strength, or a
combination thereof.
24. The method of claim 16, wherein each of the grant and one or
more additional grants for the first set of uplink resources
comprises respective channel access procedure parameters for the
first set of uplink resources or the second set of uplink
resources, and receiving the radio resource control connection
request message from the UE is based at least in part on the
successful result of the channel access procedure according to the
respective channel access procedure parameters, and wherein the
channel access procedure parameters comprise a channel access
priority, channel occupancy time information, or a combination
thereof, associated with the corresponding first set of uplink
resources or second set of uplink resources.
25. An apparatus for wireless communications at a user equipment
(UE), comprising: a processor, memory coupled with the processor;
and instructions stored in the memory, wherein the instructions are
executable by the processor to: transmit a random access request
message to a base station; receive a random access response message
from the base station in response to the random access request
message, the random access response message comprising a grant for
a first set of uplink resources for transmitting a radio resource
control connection request message to the base station; determine
at least a second set of uplink resources for transmitting the
radio resource control connection request message to the base
station based at least in part on a relationship between the first
set of uplink resources and the second set of uplink resources, and
the grant for the first set of uplink resources; perform a channel
access procedure for both the first set of uplink resources and the
second set of uplink resources; transmit, based at least in part on
performing the channel access procedure, the radio resource control
connection request message to the base station using one or more of
the first set of uplink resources or the second set of uplink
resources; and establish a connection with the base station based
at least in part on the radio resource control connection request
message.
26. The apparatus of claim 25, wherein the instructions are further
executable by the processor to: receive timing information from the
base station, the timing information indicating a time-domain
offset between the random access response message, the one or more
of the first set of uplink resources, the second set of uplink
resources, or a combination thereof; and transmit the radio
resource control connection request message according to the timing
information.
27. The apparatus of claim 25, wherein the instructions are further
executable by the processor to: receive a multiple grant
configuration in a system information block message, a remaining
minimum system information message, a dedicated signaling message,
or a combination thereof.
28. An apparatus for wireless communications at a base station,
comprising: a processor, memory coupled with the processor; and
instructions stored in the memory and executable by the processor
to: receive a random access request message from a user equipment
(UE); transmit a random access response message to the UE in
response to the random access request message, the random access
response message comprising a grant for a first set of uplink
resources for receiving a radio resource control connection request
message from the UE; receive the radio resource control connection
request message from the UE using one or more of the first set of
uplink resources or a second set of uplink resources, wherein one
or both of the first set of uplink resources or the second set of
uplink resources corresponds to a successful channel access
procedure, and wherein the second set of uplink resources is based
at least in part on a relationship between the first set of uplink
resources and the second set of uplink resources, and the grant for
the first set of uplink resources; and establish a connection with
the UE based at least in part on the radio resource control
connection request message.
29. The apparatus of claim 28, wherein the instructions are further
executable by the processor to: transmit timing information to the
UE, the timing information indicating a time-domain offset between
the random access response message, the one or more of the first
set of uplink resources, the second set of uplink resources, or a
combination thereof; and receive the radio resource control
connection request message according to the timing information.
30. The apparatus of claim 28, wherein the instructions are further
executable by the processor to: receive a repeated transmission of
the radio resource control connection request message from the UE
using one or more of the first set of uplink resources or the
second set of uplink resources.
Description
BACKGROUND
The following relates generally to wireless communications, and
more specifically to techniques for using multiple sets of uplink
resources in a random access procedure.
Wireless communications systems are widely deployed to provide
various types of communication content such as voice, video, packet
data, messaging, broadcast, and so on. These systems may be capable
of supporting communication with multiple users by sharing the
available system resources (e.g., time, frequency, and power).
Examples of such multiple-access systems include fourth generation
(4G) systems such as Long Term Evolution (LTE) systems,
LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth
generation (5G) systems which may be referred to as New Radio (NR)
systems. These systems may employ technologies such as code
division multiple access (CDMA), time division multiple access
(TDMA), frequency division multiple access (FDMA), orthogonal
frequency division multiple access (OFDMA), or discrete Fourier
transform spread orthogonal frequency division multiplexing
(DFT-s-OFDM). A wireless multiple-access communications system may
include a number of base stations or network access nodes, each
simultaneously supporting communication for multiple communication
devices, which may be otherwise known as user equipment (UE).
To access a wireless network, a UE may perform a random access
procedure with a base station using a set of resources (e.g., a set
of time, frequency, and/or spatial resources). In some cases, other
communications devices (e.g., other UEs, base stations, etc.) in
the vicinity may communicate transmissions using a set of resources
at least partially overlapping the set of resources to be used for
the random access procedure. In some cases, a message communicated
as part of the random access procedure between the UE and the base
station may collide with the communications between the nearby
communications device (e.g., when the communications are
transmitted using overlapping sets of resources). The collision may
cause the UE to fail to successfully perform the random access
procedure, in which case the UE may restart a new random access
procedure to again attempt to access the wireless network.
SUMMARY
The described techniques relate to improved methods, systems,
devices, and apparatuses that support techniques for using multiple
sets of uplink resources in a random access procedure. Generally,
the described techniques provide for a user equipment (UE)
performing a random access procedure (e.g., a random access channel
(RACH) procedure) with a base station to access a wireless network.
In the random access procedure, the UE and base station may
communicate, for example, a random access request message, a random
access response message, a radio resource control (RRC) connection
request message, and/or a contention resolution message. Each of
the messages may be communicated using respective sets of resources
(e.g., a set of time, frequency, and/or spatial resources). In some
cases, the UE and base station may perform listen-before-talk (LBT)
procedures before one or more of the messages of the random access
procedure, for example, to prevent collisions with communications
from other nearby wireless communications devices (e.g., in a
shared or unlicensed radio frequency spectrum bandwidth).
To start the random access procedure, the UE may transmit a random
access request message to the base station using a set of resources
(e.g., a set of RACH resources). The random access request message
may be, for example, a physical random access channel (PRACH)
transmission transmitted using a set of resources allocated for
PRACH transmissions. In some cases, the random access request
message may, for example, include a random access preamble that
identifies the random access request message corresponding to the
UE. In response to the random access request message, the base
station may transmit to the UE a random access response message,
where the random access response message may include a grant for a
first set of uplink resources (e.g., a set of time, frequency,
and/or spatial resources) for transmitting the RRC connection
request message to the base station.
In some cases, the UE may further determine a second set of uplink
resources for transmitting the RRC connection request message to
the base station based on the grant for the first set of uplink
resources. For example, the base station may convey multiple uplink
grants to the UE, where each uplink grant indicates a respective
allocation of set of uplink resources with which the UE may
transmit the RRC connection request message (or, multiple
repetitions of the RRC connection request message). Alternatively,
the UE may derive one or more additional grants implicitly based on
the first uplink grant received from the base station, the derived
grants similarly indicating respective allocations of sets of
uplink resources for the UE to transmit the RRC connection request
message. The UE may transmit the RRC connection request message to
the base station using one or more of the first set of uplink
resources or the second set of uplink resources. Based on the RRC
connection request message, the UE and base station may establish a
configured connection for communicating subsequent uplink and
downlink messages.
A method of wireless communications at a UE is described. The
method may include transmitting a random access request message to
a base station, receiving a random access response message from the
base station in response to the random access request message, the
random access response message including a grant for a first set of
uplink resources for transmitting an RRC connection request message
to the base station, determining at least a second set of uplink
resources for transmitting the RRC connection request message to
the base station based on the grant for the first set of uplink
resources, transmitting the RRC connection request message to the
base station using one or more of the first set of uplink resources
or the second set of uplink resources, and establishing a
connection with the base station based on the RRC connection
request message.
An apparatus for wireless communications at a UE is described. The
apparatus may include a processor, memory in electronic
communication with the processor, and instructions stored in the
memory. The instructions may be executable by the processor to
cause the apparatus to transmit a random access request message to
a base station, receive a random access response message from the
base station in response to the random access request message, the
random access response message including a grant for a first set of
uplink resources for transmitting an RRC connection request message
to the base station, determine at least a second set of uplink
resources for transmitting the RRC connection request message to
the base station based on the grant for the first set of uplink
resources, transmit the RRC connection request message to the base
station using one or more of the first set of uplink resources or
the second set of uplink resources, and establish a connection with
the base station based on the RRC connection request message.
Another apparatus for wireless communications at a UE is described.
The apparatus may include means for transmitting a random access
request message to a base station, receiving a random access
response message from the base station in response to the random
access request message, the random access response message
including a grant for a first set of uplink resources for
transmitting an RRC connection request message to the base station,
determining at least a second set of uplink resources for
transmitting the RRC connection request message to the base station
based on the grant for the first set of uplink resources,
transmitting the RRC connection request message to the base station
using one or more of the first set of uplink resources or the
second set of uplink resources, and establishing a connection with
the base station based on the RRC connection request message.
A non-transitory computer-readable medium storing code for wireless
communications at a UE is described. The code may include
instructions executable by a processor to transmit a random access
request message to a base station, receive a random access response
message from the base station in response to the random access
request message, the random access response message including a
grant for a first set of uplink resources for transmitting an RRC
connection request message to the base station, determine at least
a second set of uplink resources for transmitting the RRC
connection request message to the base station based on the grant
for the first set of uplink resources, transmit the RRC connection
request message to the base station using one or more of the first
set of uplink resources or the second set of uplink resources, and
establish a connection with the base station based on the RRC
connection request message.
Some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein may further include
operations, features, means, or instructions for receiving a
multiple grant configuration in a system information block (SIB)
message, a remaining minimum system information (RMSI) message, a
dedicated signaling message, or a combination thereof. Some
examples of the method, apparatuses, and non-transitory
computer-readable medium described herein may further include
operations, features, means, or instructions for determining at
least the second set of uplink resources for transmitting the RRC
connection request message to the base station based on the
multiple grant configuration. In some examples of the method,
apparatuses, and non-transitory computer-readable medium described
herein, the multiple grant configuration indicates a maximum number
of grants, a relationship between the first set of uplink resources
and the second set of uplink resources, a modulation and coding
scheme (MCS), or a combination thereof.
Some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein may further include
operations, features, means, or instructions for repeating
transmission of the RRC connection request message to the base
station using one or more of the first set of uplink resources or
the second set of uplink resources. In some examples of the method,
apparatuses, and non-transitory computer-readable medium described
herein, the random access response message includes grant
multiplicity information, the grant multiplicity information
indicating a number of grants to be used for repeating transmission
of the RRC connection request message, and where repeating
transmission of the RRC connection request message to the base
station may be based on the grant multiplicity information.
In some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein, the random access
response message includes one or more additional grants for at
least the second set of uplink resources, and determining at least
the second set of uplink resources may be based on the one or more
additional grants. In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, each of
the grant and the one or more additional grants includes a random
access preamble identifier for transmitting the RRC connection
request message, each of the random access preamble identifiers of
each of the grant and the one or more additional grants having a
same value. In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, each of
the grant and the one or more additional grants includes a random
access preamble identifier for transmitting the RRC connection
request message, one or more of the random access preamble
identifiers of the grant and the one or more additional grants
having different values.
In some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein, each of the grant and
the one or more additional grants includes a temporary cell
identifier for transmitting the RRC connection request message,
each of the temporary cell identifiers of each of the grant and the
one or more additional grants having a same value. In some examples
of the method, apparatuses, and non-transitory computer-readable
medium described herein, each of the grant and the one or more
additional grants includes a temporary cell identifier for
transmitting the RRC connection request message, one or more of the
temporary cell identifiers of the grant and the one or more
additional grants having different values.
Some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein may further include
operations, features, means, or instructions for receiving timing
information from the base station, the timing information
indicating a time-domain offset between the random access response
message, the one or more of the first set of uplink resources, the
second set of uplink resources, or a combination thereof, and
transmitting the RRC connection request message according to the
timing information.
Some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein may further include
operations, features, means, or instructions for transmitting the
RRC connection request message using whichever of the first set of
uplink resources or the second set of uplink resources may have an
earliest time component.
Some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein may further include
operations, features, means, or instructions for performing a
channel access procedure for both the first set of uplink resources
and the second set of uplink resources, and transmitting the RRC
connection request message using whichever of the first set of
uplink resources or the second set of uplink resources corresponds
to a first successful channel access procedure.
In some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein, each of the grant and
the one or more additional grants includes respective channel
access procedure parameters for the first set of uplink resources
or the second set of uplink resources, and transmitting the RRC
connection request message to the base station may be based on a
successful result of one or more of the channel access procedures
according to the respective channel access procedure parameters. In
some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein, the channel access
procedure parameters include a channel access priority, channel
occupancy time (COT) information, or a combination thereof,
associated with the corresponding first set of uplink resources or
second set of uplink resources.
Some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein may further include
operations, features, means, or instructions for determining a
signal strength associated with each of the first set of uplink
resources and the second set of uplink resources, and transmitting
the RRC connection request message using whichever of the first set
of uplink resources or the second set of uplink resources may be
associated with a greatest signal strength (e.g., the base station
and UE may map each preamble of one or more random access request
messages to a corresponding synchronization signal block (SSB)
index or group of SSB indexes, and an index of the preambles may
map to corresponding random access preamble identifiers (RAPIDs),
such that the base station and/or the UE may use the RAPIDs to
identify particular beams or sets of beams with a greatest signal
strength to be used to transmit the RRC connection request
message).
In some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein, the random access
response message indicates beam information associated with the
grant for the first set of uplink resources, and beam parameters
for an uplink beam to be used to transmit the RRC connection
request message may be based on the beam information. Some examples
of the method, apparatuses, and non-transitory computer-readable
medium described herein may further include operations, features,
means, or instructions for determining the uplink beam to be used
to transmit the RRC connection request message to the base station
based on the beam parameters for the uplink beam, and transmitting
the RRC connection request message to the base station using the
uplink beam.
In some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein, the beam information
indicates a mapping of one or more beam indexes according to one or
more corresponding random access preamble identifiers. In some
examples of the method, apparatuses, and non-transitory
computer-readable medium described herein, the beam information
indicates one or more downlink beam parameters for a downlink beam
used to receive synchronization signals from the base station, and
determining the uplink beam to be used to transmit the RRC
connection request message may be based on a correspondence between
the downlink beam parameters and the uplink beam parameters for the
uplink beam. In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, the
downlink beam used to receive the synchronization signals from the
base station may be different than a second downlink beam used to
receive the random access response message from the base
station.
A method of wireless communications at a base station is described.
The method may include receiving a random access request message
from a UE, transmitting a random access response message to the UE
in response to the random access request message, the random access
response message including a grant for a first set of uplink
resources for receiving an RRC connection request message from the
UE, receiving the RRC connection request message from the UE using
one or more of the first set of uplink resources or a second set of
uplink resources, the second set of uplink resources based on the
grant for the first set of uplink resources, and establishing a
connection with the UE based on the RRC connection request
message.
An apparatus for wireless communications at a base station is
described. The apparatus may include a processor, memory in
electronic communication with the processor, and instructions
stored in the memory. The instructions may be executable by the
processor to cause the apparatus to receive a random access request
message from a UE, transmit a random access response message to the
UE in response to the random access request message, the random
access response message including a grant for a first set of uplink
resources for receiving an RRC connection request message from the
UE, receive the RRC connection request message from the UE using
one or more of the first set of uplink resources or a second set of
uplink resources, the second set of uplink resources based on the
grant for the first set of uplink resources, and establish a
connection with the UE based on the RRC connection request
message.
Another apparatus for wireless communications at a base station is
described. The apparatus may include means for receiving a random
access request message from a UE, transmitting a random access
response message to the UE in response to the random access request
message, the random access response message including a grant for a
first set of uplink resources for receiving an RRC connection
request message from the UE, receiving the RRC connection request
message from the UE using one or more of the first set of uplink
resources or a second set of uplink resources, the second set of
uplink resources based on the grant for the first set of uplink
resources, and establishing a connection with the UE based on the
RRC connection request message.
A non-transitory computer-readable medium storing code for wireless
communications at a base station is described. The code may include
instructions executable by a processor to receive a random access
request message from a UE, transmit a random access response
message to the UE in response to the random access request message,
the random access response message including a grant for a first
set of uplink resources for receiving an RRC connection request
message from the UE, receive the RRC connection request message
from the UE using one or more of the first set of uplink resources
or a second set of uplink resources, the second set of uplink
resources based on the grant for the first set of uplink resources,
and establish a connection with the UE based on the RRC connection
request message.
Some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein may further include
operations, features, means, or instructions for receiving a
repeated transmission of the RRC connection request message from
the UE using one or more of the first set of uplink resources or
the second set of uplink resources. In some examples of the method,
apparatuses, and non-transitory computer-readable medium described
herein, the repeated transmission of the RRC connection request
message to the base station may be based on grant multiplicity
information included in the random access response message.
In some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein, the random access
response message includes one or more additional grants for the
first set of uplink resources, and the second set of uplink
resources may be based on the one or more additional grants for the
first set of uplink resources. In some examples of the method,
apparatuses, and non-transitory computer-readable medium described
herein, each of the grant and the one or more additional grants
includes a random access preamble identifier for transmitting the
RRC connection request message, each of the random access preamble
identifiers of each of the grant and the one or more additional
grants having a same value.
In some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein, each of the grant and
the one or more additional grants includes a random access preamble
identifier for transmitting the RRC connection request message, one
or more of the random access preamble identifiers of the grant and
the one or more additional grants having different values. In some
examples of the method, apparatuses, and non-transitory
computer-readable medium described herein, each of the grant and
the one or more additional grants includes a temporary cell
identifier for transmitting the RRC connection request message,
each of the temporary cell identifiers of each of the grant and the
one or more additional grants having a same value. In some examples
of the method, apparatuses, and non-transitory computer-readable
medium described herein, each of the grant and the one or more
additional grants includes a temporary cell identifier for
transmitting the RRC connection request message, one or more of the
temporary cell identifiers of the grant and the one or more
additional grants having different values.
Some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein may further include
operations, features, means, or instructions for transmitting
timing information to the UE, the timing information indicating a
time-domain offset between the random access response message, the
one or more of the first set of uplink resources, the second set of
uplink resources, or a combination thereof, and receiving the RRC
connection request message according to the timing information.
Some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein may further include
operations, features, means, or instructions for receiving the RRC
connection request message using whichever of the first set of
uplink resources or the second set of uplink resources may have an
earliest time component. Some examples of the method, apparatuses,
and non-transitory computer-readable medium described herein may
further include operations, features, means, or instructions for
receiving the RRC connection request message using whichever of the
first set of uplink resources or the second set of uplink resources
corresponds to a first successful channel access procedure.
In some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein, each of the grant and
the one or more additional grants includes respective channel
access procedure parameters for the first set of uplink resources
or the second set of uplink resources, and receiving the RRC
connection request message from the UE may be based on a successful
result of one or more of the channel access procedures according to
the respective channel access procedure parameters. In some
examples of the method, apparatuses, and non-transitory
computer-readable medium described herein, the channel access
procedure parameters include a channel access priority, COT
information, or a combination thereof, associated with the
corresponding first set of uplink resources or second set of uplink
resources.
Some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein may further include
operations, features, means, or instructions for receiving the RRC
connection request message using whichever of the first set of
uplink resources or the second set of uplink resources may be
associated with a greatest signal strength.
Some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein may further include
operations, features, means, or instructions for identifying beam
information associated with the grant for the first set of uplink
resources, where the random access response message indicates the
beam information, and beam parameters for an uplink beam used to
receive the RRC connection request message may be based on the beam
information. Some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein may
further include operations, features, means, or instructions for
receiving the RRC connection request message from the UE using the
uplink beam according to the beam parameters. In some examples of
the method, apparatuses, and non-transitory computer-readable
medium described herein, the beam information indicates a mapping
of one or more beam indexes according to one or more corresponding
random access preamble identifiers.
In some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein, the beam information
indicates one or more downlink beam parameters for a downlink beam
used to transmit synchronization signals to the UE, and the uplink
beam used to receive the RRC connection request message may be
based on a correspondence between the downlink beam parameters and
the uplink beam parameters for the uplink beam. In some examples of
the method, apparatuses, and non-transitory computer-readable
medium described herein, the downlink beam used to transmit the
synchronization signals to the UE may be different than a second
downlink beam used to transmit the random access response message
to the UE.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates an example of a system for wireless
communications system that supports techniques for using multiple
sets of uplink resources in a random access procedure in accordance
with aspects of the present disclosure.
FIG. 2 illustrates an example of a wireless communications system
that supports techniques for using multiple sets of uplink
resources in a random access procedure in accordance with aspects
of the present disclosure.
FIG. 3 illustrates an example of a message format for a
communications scheme that supports techniques for using multiple
sets of uplink resources in a random access procedure in accordance
with aspects of the present disclosure.
FIG. 4 illustrates an example of a message format for a
communications scheme that supports techniques for using multiple
sets of uplink resources in a random access procedure in accordance
with aspects of the present disclosure.
FIG. 5 illustrates an example of a message format for a
communications scheme that supports techniques for using multiple
sets of uplink resources in a random access procedure in accordance
with aspects of the present disclosure.
FIG. 6 illustrates an example of a message format for a
communications scheme that supports techniques for using multiple
sets of uplink resources in a random access procedure in accordance
with aspects of the present disclosure.
FIG. 7 illustrates an example of a message format for a
communications scheme that supports techniques for using multiple
sets of uplink resources in a random access procedure in accordance
with aspects of the present disclosure.
FIG. 8 illustrates an example of a process flow that supports
techniques for using multiple sets of uplink resources in a random
access procedure in accordance with aspects of the present
disclosure.
FIGS. 9 and 10 show block diagrams of devices that support
techniques for using multiple sets of uplink resources in a random
access procedure in accordance with aspects of the present
disclosure.
FIG. 11 shows a block diagram of a communications manager that
supports techniques for using multiple sets of uplink resources in
a random access procedure in accordance with aspects of the present
disclosure.
FIG. 12 shows a diagram of a system including a device that
supports techniques for using multiple sets of uplink resources in
a random access procedure in accordance with aspects of the present
disclosure.
FIGS. 13 and 14 show block diagrams of devices that support
techniques for using multiple sets of uplink resources in a random
access procedure in accordance with aspects of the present
disclosure.
FIG. 15 shows a block diagram of a communications manager that
supports techniques for using multiple sets of uplink resources in
a random access procedure in accordance with aspects of the present
disclosure.
FIG. 16 shows a diagram of a system including a device that
supports techniques for using multiple sets of uplink resources in
a random access procedure in accordance with aspects of the present
disclosure.
FIGS. 17 through 23 show flowcharts illustrating methods that
support techniques for using multiple sets of uplink resources in a
random access procedure in accordance with aspects of the present
disclosure.
DETAILED DESCRIPTION
The present disclosure describes techniques for using multiple sets
of uplink resources to avoid collisions during a random access
procedure. A user equipment (UE) may perform a random access
procedure (e.g., a random access channel (RACH) procedure) with a
base station to access a wireless network, for example, when
initially accessing the wireless network or during a handover. The
random access procedure may, for example, include a random access
request message, a random access response message, a radio resource
control (RRC) message such as an RRC connection request message,
and/or a contention resolution message. In some cases, these
messages may include, or be referred to as, a RACH Msg 1, a RACH
Msg2, a RACH Msg3, and a RACH Msg4, respectively. Each of the
messages of the random access procedure may be communicated using
corresponding sets of resources (e.g., corresponding sets of time,
frequency, and/or spatial resources).
According to the random access procedure, the UE may first transmit
a random access request message to the base station using a set of
resources (e.g., a set of RACH resources). The random access
request message may be, for example, a physical random access
channel (PRACH) transmission transmitted using a set of resources
allocated for PRACH transmissions. In some cases, the random access
request message may, for example, include a random access preamble
that identifies the random access request message corresponding to
the UE.
The base station may receive the random access request message and
may, for example, identify that the random access preamble
corresponds to the transmitting UE (e.g., according to a random
access preamble identifier (RAPID)). In response, the base station
may transmit the random access response message to the UE, where
the random access response message may include a grant for a first
set of uplink resources (e.g., a set of time, frequency, and/or
spatial resources) for transmitting the RRC connection request
message to the base station. The UE may use the uplink grant to
transmit a first scheduled uplink transmission to the base station
(e.g., the RRC connection request message for the random access
procedure). The RRC connection request message may, for example,
indicate a configuration that the base station may use to establish
a communication link with the UE, for example, including an RRC
Connection Request message, an identifier of the UE, and like
information. The base station and the UE may then communicate
uplink and downlink transmission using the configured communication
link.
In some cases, the UE and the base station may perform the random
access procedure while operating in a shared or unlicensed radio
frequency spectrum bandwidth. In some cases, other communications
devices (e.g., other UEs, base stations, etc.) in the relatively
nearby vicinity may also send transmissions using resources of the
shared radio frequency spectrum bandwidth (the resources, e.g., at
least partially overlapping a set of resources to be used for the
random access procedure). In such cases, communications to and/or
from the other devices on overlapping time, frequency, and space
resources of the shared radio frequency spectrum band may collide
with the messages communicated between the UE and the base station
for the random access procedure.
In some cases, if one message of the random access procedure is not
correctly received, the random access procedure may fail (e.g., due
to the deterministic relationship, and timings for, one message to
the next in the random access procedure). For example, if the RRC
connection request message collides with another transmission from
another device in the vicinity of the UE or the base station (the
other device transmitting using the same or an overlapping set of
resources), the base station may not correctly receive the random
access response message including the grant for the first set of
uplink resources on which to transmit the RRC connection request
message to the base station. In this case, the random access
procedure fails, and the UE and the base station may restart a new
random access procedure, for example, from the first message (e.g.,
via a new random access request message). In this way, for example,
one message collision may cause a failure to successfully complete
a random access procedure including one uplink grant in the random
access response message, which may result in inefficient resource
utilization and/or communications delays (e.g., a delay in
obtaining access to a network).
In some cases, before establishing a connection for communications
on the shared radio frequency spectrum band, the UE and/or the base
station may utilize a channel access procedure (e.g., an LBT
procedure) to determine whether the time and frequency resources
for the channel are available, which may prevent interference and
collisions with nearby communications between another UE and the
base station, another UE and another base station, higher priority
transmissions (e.g., radar), etc. For example, before one or more
of the messages of the random access procedure, the UE and/or the
base station may perform an opportunistic contention-based channel
access procedure (e.g., a listen-before-talk (LBT) procedure) to
contend for access to the shared radio frequency spectrum band. In
some cases, the UE may perform a directional LBT procedure in
multiple transmission direction, for example, in a communications
system that supports relatively more directional communications
(e.g., millimeter wave (mmW) communications systems).
Moreover, in some cases, the random access procedure may fail when
the UE does not successfully perform an LBT procedure, for example,
before transmitting the RRC connection request message. That is the
UE may determine via the LBT procedure that the medium is not
available to transmit according to the allocated resources, and
thus may not transmit the RRC connection request message to the
base station. The base station may not correctly receive RRC
connection request message based on which a connection would be
established with the UE. In this case, the random access procedure
fails, and the UE and the base station may restart a new random
access procedure, for example, from the first message (e.g., via a
new random access request message). In this way, for example, a
failure to successfully complete the LBT procedure for one uplink
grant including one uplink grant may similarly cause inefficient
resource utilization and/or communications delays (e.g., a delay in
obtaining access to a network).
According to the techniques described herein, the UE and the base
station may utilize multiple sets of uplink resources to mitigate
the effects of and/or prevent such a failed LBT procedure. In some
cases, the base station may convey multiple uplink grants to the UE
so that if the medium is busy during the resources of a first
uplink grant, the UE may transmit the RRC connection request
message using resources of one or more additional uplink grants.
For example, the base station may indicate multiple sets of uplink
resources in a payload of a single random access response message.
Additionally or alternatively, the base station may configure each
of multiple uplink grants separately in separate random access
response message payloads.
Additionally or alternatively, in some cases, the base station may
indicate a grant for one set of uplink resources in the random
access response message and the UE may derive further grants
implicitly from the indicated grant. When the UE identifies
multiple sets of resources to be used for transmitting the RRC
connection request message (e.g., according to multiple uplink
grants), the UE may transmit one or more RRC connection request
messages using the resources allocated by more than one of the
uplink grants (e.g., using the resources of each of the uplink
grants or as implicitly derived at the UE). Accordingly, the
described techniques provide for flexible scheduling of uplink
grants such that the base station may be able to more dynamically
account for network conditions.
Further, for directional communications using different directional
transmit beams, the base station may include beam information in
the random access response message indicating one or more beams to
be used for transmitting the RRC connection request message. In
some cases, the UE may identify one or more uplink beams to be used
to transmit the RRC connection request message according to a beam
correspondence based on the random access response message (e.g., a
known correspondence between uplink and downlink beams). For
example, the base station and UE may map each preamble of one or
more random access request messages to a corresponding
synchronization signal block (SSB) index or group of SSB indexes,
and an index of the preambles may map to corresponding RAPIDs, such
that the base station and/or the UE may use the RAPIDs to identify
particular beams or sets of beams with particular beam parameters
to be used to transmit the RRC connection request message. In this
way, the base station may identify for the UE a particular beam via
its corresponding RAPID even though the UE did not transmit the
random access request message using the corresponding RAPID.
In some cases, the UE use determine a signal strength associated
with each beams indicated via the corresponding RAPIDs, and the UE
may determine to transmit one or more RRC connection request
messages using a transmit beam for which the UE determined to have
a strongest signal strength (or multiple transmit beams with the
strongest signal strengths). In some such cases where the UE
determines uplink resources having the greatest signal strength for
the respective beams from each of the uplink resources, the UE may
use the RAPIDs or SSB indexes to identify the SSBs from which to
select the resources (or beam) having the strongest signal
strength. The UE may then select the uplink resources via the beam
correspondence with the SSB that has the strongest signal
strength.
Aspects of the disclosure are initially described in the context of
a wireless communications system. Aspects of the disclosure are
also described in the context of message formats and a process flow
that relate to configuring uplink control channel resources for
communications in a shared radio frequency spectrum. Aspects of the
disclosure are further illustrated by and described with reference
to apparatus diagrams, system diagrams, and flowcharts that relate
to techniques for using multiple sets of uplink resources in a
random access procedure.
FIG. 1 illustrates an example of a wireless communications system
100 that supports techniques for using multiple sets of uplink
resources in a random access procedure in accordance with aspects
of the present disclosure. The wireless communications system 100
includes base stations 105, UEs 115, and a core network 130. In
some examples, the wireless communications system 100 may be a Long
Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an
LTE-A Pro network, or a New Radio (NR) network. In some cases,
wireless communications system 100 may support enhanced broadband
communications, ultra-reliable (e.g., mission critical)
communications, low latency communications, or communications with
low-cost and low-complexity devices.
Base stations 105 may wirelessly communicate with UEs 115 via one
or more base station antennas. Base stations 105 described herein
may include or may be referred to by those skilled in the art as a
base transceiver station, a radio base station, an access point, a
radio transceiver, a NodeB, an eNodeB (eNB), a next-generation
NodeB or giga-NodeB (either of which may be referred to as a gNB),
a Home NodeB, a Home eNodeB, or some other suitable terminology.
Wireless communications system 100 may include base stations 105 of
different types (e.g., macro or small cell base stations). The UEs
115 described herein may be able to communicate with various types
of base stations 105 and network equipment including macro eNBs,
small cell eNBs, gNBs, relay base stations, and the like.
Each base station 105 may be associated with a particular
geographic coverage area 110 in which communications with various
UEs 115 is supported. Each base station 105 may provide
communication coverage for a respective geographic coverage area
110 via communication links 125, and communication links 125
between a base station 105 and a UE 115 may utilize one or more
carriers. Communication links 125 shown in wireless communications
system 100 may include uplink transmissions from a UE 115 to a base
station 105, or downlink transmissions from a base station 105 to a
UE 115. Downlink transmissions may also be called forward link
transmissions while uplink transmissions may also be called reverse
link transmissions.
The geographic coverage area 110 for a base station 105 may be
divided into sectors making up a portion of the geographic coverage
area 110, and each sector may be associated with a cell. For
example, each base station 105 may provide communication coverage
for a macro cell, a small cell, a hot spot, or other types of
cells, or various combinations thereof. In some examples, a base
station 105 may be movable and therefore provide communication
coverage for a moving geographic coverage area 110. In some
examples, different geographic coverage areas 110 associated with
different technologies may overlap, and overlapping geographic
coverage areas 110 associated with different technologies may be
supported by the same base station 105 or by different base
stations 105. The wireless communications system 100 may include,
for example, a heterogeneous LTE/LTE-A/LTE-A Pro or NR network in
which different types of base stations 105 provide coverage for
various geographic coverage areas 110.
The term "cell" refers to a logical communication entity used for
communication with a base station 105 (e.g., over a carrier), and
may be associated with an identifier for distinguishing neighboring
cells (e.g., a physical cell identifier (PCID), a virtual cell
identifier (VCID)) operating via the same or a different carrier.
In some examples, a carrier may support multiple cells, and
different cells may be configured according to different protocol
types (e.g., machine-type communication (MTC), narrowband
Internet-of-Things (NB-IoT), enhanced mobile broadband (eMBB), or
others) that may provide access for different types of devices. In
some cases, the term "cell" may refer to a portion of a geographic
coverage area 110 (e.g., a sector) over which the logical entity
operates.
UEs 115 may be dispersed throughout the wireless communications
system 100, and each UE 115 may be stationary or mobile. A UE 115
may also be referred to as a mobile device, a wireless device, a
remote device, a handheld device, or a subscriber device, or some
other suitable terminology, where the "device" may also be referred
to as a unit, a station, a terminal, or a client. A UE 115 may also
be a personal electronic device such as a cellular phone, a
personal digital assistant (PDA), a tablet computer, a laptop
computer, or a personal computer. In some examples, a UE 115 may
also refer to a wireless local loop (WLL) station, an Internet of
Things (IoT) device, an Internet of Everything (IoE) device, or an
MTC device, or the like, which may be implemented in various
articles such as appliances, vehicles, meters, or the like.
Some UEs 115, such as MTC or IoT devices, may be low cost or low
complexity devices, and may provide for automated communication
between machines (e.g., via Machine-to-Machine (M2M)
communication). M2M communication or MTC may refer to data
communication technologies that allow devices to communicate with
one another or a base station 105 without human intervention. In
some examples, M2M communication or MTC may include communications
from devices that integrate sensors or meters to measure or capture
information and relay that information to a central server or
application program that can make use of the information or present
the information to humans interacting with the program or
application. Some UEs 115 may be designed to collect information or
enable automated behavior of machines. Examples of applications for
MTC devices include smart metering, inventory monitoring, water
level monitoring, equipment monitoring, healthcare monitoring,
wildlife monitoring, weather and geological event monitoring, fleet
management and tracking, remote security sensing, physical access
control, and transaction-based business charging.
Some UEs 115 may be configured to employ operating modes that
reduce power consumption, such as half-duplex communications (e.g.,
a mode that supports one-way communication via transmission or
reception, but not transmission and reception simultaneously). In
some examples half-duplex communications may be performed at a
reduced peak rate. Other power conservation techniques for UEs 115
include entering a power saving "deep sleep" mode when not engaging
in active communications, or operating over a limited bandwidth
(e.g., according to narrowband communications). In some cases, UEs
115 may be designed to support critical functions (e.g., mission
critical functions), and a wireless communications system 100 may
be configured to provide ultra-reliable communications for these
functions.
In some cases, a UE 115 may also be able to communicate directly
with other UEs 115 (e.g., using a peer-to-peer (P2P) or
device-to-device (D2D) protocol). One or more of a group of UEs 115
utilizing D2D communications may be within the geographic coverage
area 110 of a base station 105. Other UEs 115 in such a group may
be outside the geographic coverage area 110 of a base station 105,
or be otherwise unable to receive transmissions from a base station
105. In some cases, groups of UEs 115 communicating via D2D
communications may utilize a one-to-many (1:M) system in which each
UE 115 transmits to every other UE 115 in the group. In some cases,
a base station 105 facilitates the scheduling of resources for D2D
communications. In other cases, D2D communications are carried out
between UEs 115 without the involvement of a base station 105.
Base stations 105 may communicate with the core network 130 and
with one another. For example, base stations 105 may interface with
the core network 130 through backhaul links 132 (e.g., via an S1,
N2, N3, or other interface). Base stations 105 may communicate with
one another over backhaul links 134 (e.g., via an X2, Xn, or other
interface) either directly (e.g., directly between base stations
105) or indirectly (e.g., via core network 130).
The core network 130 may provide user authentication, access
authorization, tracking, Internet Protocol (IP) connectivity, and
other access, routing, or mobility functions. The core network 130
may be an evolved packet core (EPC), which may include at least one
mobility management entity (MME), at least one serving gateway
(S-GW), and at least one Packet Data Network (PDN) gateway (P-GW).
The MME may manage non-access stratum (e.g., control plane)
functions such as mobility, authentication, and bearer management
for UEs 115 served by base stations 105 associated with the EPC.
User IP packets may be transferred through the S-GW, which itself
may be connected to the P-GW. The P-GW may provide IP address
allocation as well as other functions. The P-GW may be connected to
the network operators IP services. The operators IP services may
include access to the Internet, Intranet(s), an IP Multimedia
Subsystem (IMS), or a Packet-Switched (PS) Streaming Service.
At least some of the network devices, such as a base station 105,
may include subcomponents such as an access network entity, which
may be an example of an access node controller (ANC). Each access
network entity may communicate with UEs 115 through a number of
other access network transmission entities, which may be referred
to as a radio head, a smart radio head, or a transmission/reception
point (TRP). In some configurations, various functions of each
access network entity or base station 105 may be distributed across
various network devices (e.g., radio heads and access network
controllers) or consolidated into a single network device (e.g., a
base station 105).
Wireless communications system 100 may operate using one or more
frequency bands, typically in the range of 300 megahertz (MHz) to
300 gigahertz (GHz). Generally, the region from 300 MHz to 3 GHz is
known as the ultra-high frequency (UHF) region or decimeter band,
since the wavelengths range from approximately one decimeter to one
meter in length. UHF waves may be blocked or redirected by
buildings and environmental features. However, the waves may
penetrate structures sufficiently for a macro cell to provide
service to UEs 115 located indoors. Transmission of UHF waves may
be associated with smaller antennas and shorter range (e.g., less
than 100 km) compared to transmission using the smaller frequencies
and longer waves of the high frequency (HF) or very high frequency
(VHF) portion of the spectrum below 300 MHz.
Wireless communications system 100 may also operate in a super high
frequency (SHF) region using frequency bands from 3 GHz to 30 GHz,
also known as the centimeter band. The SHF region includes bands
such as the 5 GHz industrial, scientific, and medical (ISM) bands,
which may be used opportunistically by devices that may be capable
of tolerating interference from other users.
Wireless communications system 100 may also operate in an extremely
high frequency (EHF) region of the spectrum (e.g., from 30 GHz to
300 GHz), also known as the millimeter band. In some examples,
wireless communications system 100 may support millimeter wave
(mmW) communications between UEs 115 and base stations 105, and EHF
antennas of the respective devices may be even smaller and more
closely spaced than UHF antennas. In some cases, this may
facilitate use of antenna arrays within a UE 115. However, the
propagation of EHF transmissions may be subject to even greater
atmospheric attenuation and shorter range than SHF or UHF
transmissions. Techniques disclosed herein may be employed across
transmissions that use one or more different frequency regions, and
designated use of bands across these frequency regions may differ
by country or regulating body.
In some cases, wireless communications system 100 may utilize both
licensed and unlicensed radio frequency spectrum bands. For
example, wireless communications system 100 may employ License
Assisted Access (LAA), LTE-Unlicensed (LTE-U) radio access
technology, or NR technology in an unlicensed band such as the 5
GHz ISM band. When operating in unlicensed radio frequency spectrum
bands, wireless devices such as base stations 105 and UEs 115 may
employ LBT procedures to ensure a frequency channel is clear before
transmitting data. In some cases, operations in unlicensed bands
may be based on a carrier aggregation configuration in conjunction
with component carriers operating in a licensed band (e.g., LAA).
Operations in unlicensed spectrum may include downlink
transmissions, uplink transmissions, peer-to-peer transmissions, or
a combination of these. Duplexing in unlicensed spectrum may be
based on frequency division duplexing (FDD), time division
duplexing (TDD), or a combination of both.
In some examples, base station 105 or UE 115 may be equipped with
multiple antennas, which may be used to employ techniques such as
transmit diversity, receive diversity, multiple-input
multiple-output (MIMO) communications, or beamforming. For example,
wireless communications system 100 may use a transmission scheme
between a transmitting device (e.g., a base station 105) and a
receiving device (e.g., a UE 115), where the transmitting device is
equipped with multiple antennas and the receiving device is
equipped with one or more antennas. MIMO communications may employ
multipath signal propagation to increase the spectral efficiency by
transmitting or receiving multiple signals via different spatial
layers, which may be referred to as spatial multiplexing. The
multiple signals may, for example, be transmitted by the
transmitting device via different antennas or different
combinations of antennas. Likewise, the multiple signals may be
received by the receiving device via different antennas or
different combinations of antennas. Each of the multiple signals
may be referred to as a separate spatial stream, and may carry bits
associated with the same data stream (e.g., the same codeword) or
different data streams. Different spatial layers may be associated
with different antenna ports used for channel measurement and
reporting. MIMO techniques include single-user MIMO (SU-MIMO) where
multiple spatial layers are transmitted to the same receiving
device, and multiple-user MIMO (MU-MIMO) where multiple spatial
layers are transmitted to multiple devices.
Beamforming, which may also be referred to as spatial filtering,
directional transmission, or directional reception, is a signal
processing technique that may be used at a transmitting device or a
receiving device (e.g., a base station 105 or a UE 115) to shape or
steer an antenna beam (e.g., a transmit beam or receive beam) along
a spatial path between the transmitting device and the receiving
device. Beamforming may be achieved by combining the signals
communicated via antenna elements of an antenna array such that
signals propagating at particular orientations with respect to an
antenna array experience constructive interference while others
experience destructive interference. The adjustment of signals
communicated via the antenna elements may include a transmitting
device or a receiving device applying certain amplitude and phase
offsets to signals carried via each of the antenna elements
associated with the device. The adjustments associated with each of
the antenna elements may be defined by a beamforming weight set
associated with a particular orientation (e.g., with respect to the
antenna array of the transmitting device or receiving device, or
with respect to some other orientation).
In one example, a base station 105 may use multiple antennas or
antenna arrays to conduct beamforming operations for directional
communications with a UE 115. For instance, some signals (e.g.,
synchronization signals, reference signals, beam selection signals,
or other control signals) may be transmitted by a base station 105
multiple times in different directions, which may include a signal
being transmitted according to different beamforming weight sets
associated with different directions of transmission. Transmissions
in different beam directions may be used to identify (e.g., by the
base station 105 or a receiving device, such as a UE 115) a beam
direction for subsequent transmission and/or reception by the base
station 105.
Some signals, such as data signals associated with a particular
receiving device, may be transmitted by a base station 105 in a
single beam direction (e.g., a direction associated with the
receiving device, such as a UE 115). In some examples, the beam
direction associated with transmissions along a single beam
direction may be determined based on a signal that was transmitted
in different beam directions. For example, a UE 115 may receive one
or more of the signals transmitted by the base station 105 in
different directions, and the UE 115 may report to the base station
105 an indication of the signal it received with a highest signal
quality, or an otherwise acceptable signal quality. Although these
techniques are described with reference to signals transmitted in
one or more directions by a base station 105, a UE 115 may employ
similar techniques for transmitting signals multiple times in
different directions (e.g., for identifying a beam direction for
subsequent transmission or reception by the UE 115), or
transmitting a signal in a single direction (e.g., for transmitting
data to a receiving device).
A receiving device (e.g., a UE 115, which may be an example of a
mmW receiving device) may try multiple receive beams when receiving
various signals from the base station 105, such as synchronization
signals, reference signals, beam selection signals, or other
control signals. For example, a receiving device may try multiple
receive directions by receiving via different antenna subarrays, by
processing received signals according to different antenna
subarrays, by receiving according to different receive beamforming
weight sets applied to signals received at a plurality of antenna
elements of an antenna array, or by processing received signals
according to different receive beamforming weight sets applied to
signals received at a plurality of antenna elements of an antenna
array, any of which may be referred to as "listening" according to
different receive beams or receive directions. In some examples a
receiving device may use a single receive beam to receive along a
single beam direction (e.g., when receiving a data signal). The
single receive beam may be aligned in a beam direction determined
based on listening according to different receive beam directions
(e.g., a beam direction determined to have a highest signal
strength, highest signal-to-noise ratio, or otherwise acceptable
signal quality based on listening according to multiple beam
directions).
In some cases, the antennas of a base station 105 or UE 115 may be
located within one or more antenna arrays, which may support MIMO
operations, or transmit or receive beamforming. For example, one or
more base station antennas or antenna arrays may be co-located at
an antenna assembly, such as an antenna tower. In some cases,
antennas or antenna arrays associated with a base station 105 may
be located in diverse geographic locations. A base station 105 may
have an antenna array with a number of rows and columns of antenna
ports that the base station 105 may use to support beamforming of
communications with a UE 115. Likewise, a UE 115 may have one or
more antenna arrays that may support various MIMO or beamforming
operations.
In some cases, wireless communications system 100 may be a
packet-based network that operate according to a layered protocol
stack. In the user plane, communications at the bearer or Packet
Data Convergence Protocol (PDCP) layer may be IP-based. A Radio
Link Control (RLC) layer may perform packet segmentation and
reassembly to communicate over logical channels. A Medium Access
Control (MAC) layer may perform priority handling and multiplexing
of logical channels into transport channels. The MAC layer may also
use hybrid automatic repeat request (HARQ) to provide
retransmission at the MAC layer to improve link efficiency. In the
control plane, the RRC protocol layer may provide establishment,
configuration, and maintenance of an RRC connection between a UE
115 and a base station 105 or core network 130 supporting radio
bearers for user plane data. At the Physical layer, transport
channels may be mapped to physical channels.
In some cases, UEs 115 and base stations 105 may support
retransmissions of data to increase the likelihood that data is
received successfully. HARQ feedback is one technique of increasing
the likelihood that data is received correctly over a communication
link 125. HARQ may include a combination of error detection (e.g.,
using a cyclic redundancy check (CRC)), forward error correction
(FEC), and retransmission (e.g., automatic repeat request (ARQ)).
HARQ may improve throughput at the MAC layer in poor radio
conditions (e.g., signal-to-noise conditions). In some cases, a
wireless device may support same-slot HARQ feedback, where the
device may provide HARQ feedback in a specific slot for data
received in a previous symbol in the slot. In other cases, the
device may provide HARQ feedback in a subsequent slot, or according
to some other time interval.
Time intervals in LTE or NR may be expressed in multiples of a
basic time unit, which may, for example, refer to a sampling period
of T.sub.s= 1/30,720,000 seconds. Time intervals of a
communications resource may be organized according to radio frames
each having a duration of 10 milliseconds (ms), where the frame
period may be expressed as T.sub.f=307,200 T.sub.s. The radio
frames may be identified by a system frame number (SFN) ranging
from 0 to 1023. Each frame may include 10 subframes numbered from 0
to 9, and each subframe may have a duration of 1 ms. A subframe may
be further divided into 2 slots each having a duration of 0.5 ms,
and each slot may contain 6 or 7 modulation symbol periods (e.g.,
depending on the length of the cyclic prefix prepended to each
symbol period). Excluding the cyclic prefix, each symbol period may
contain 2048 sampling periods. In some cases, a subframe may be the
smallest scheduling unit of the wireless communications system 100,
and may be referred to as a transmission time interval (TTI). In
other cases, a smallest scheduling unit of the wireless
communications system 100 may be shorter than a subframe or may be
dynamically selected (e.g., in bursts of shortened TTIs (sTTIs) or
in selected component carriers using sTTIs).
In some wireless communications systems, a slot may further be
divided into multiple mini-slots containing one or more symbols. In
some instances, a symbol of a mini-slot or a mini-slot may be the
smallest unit of scheduling. Each symbol may vary in duration
depending on the subcarrier spacing or frequency band of operation,
for example. Further, some wireless communications systems may
implement slot aggregation in which multiple slots or mini-slots
are aggregated together and used for communication between a UE 115
and a base station 105.
The term "carrier" refers to a set of radio frequency spectrum
resources having a defined physical layer structure for supporting
communications over a communication link 125. For example, a
carrier of a communication link 125 may include a portion of a
radio frequency spectrum band that is operated according to
physical layer channels for a given radio access technology. Each
physical layer channel may carry user data, control information, or
other signaling. A carrier may be associated with a pre-defined
frequency channel (e.g., an evolved universal mobile
telecommunications system terrestrial radio access (E-UTRA)
absolute radio frequency channel number (EARFCN)), and may be
positioned according to a channel raster for discovery by UEs 115.
Carriers may be downlink or uplink (e.g., in an FDD mode), or be
configured to carry downlink and uplink communications (e.g., in a
TDD mode). In some examples, signal waveforms transmitted over a
carrier may be made up of multiple sub-carriers (e.g., using
multi-carrier modulation (MCM) techniques such as orthogonal
frequency division multiplexing (OFDM) or discrete Fourier
transform spread OFDM (DFT-s-OFDM)).
The organizational structure of the carriers may be different for
different radio access technologies (e.g., LTE, LTE-A, LTE-A Pro,
NR). For example, communications over a carrier may be organized
according to TTIs or slots, each of which may include user data as
well as control information or signaling to support decoding the
user data. A carrier may also include dedicated acquisition
signaling (e.g., synchronization signals or system information,
etc.) and control signaling that coordinates operation for the
carrier. In some examples (e.g., in a carrier aggregation
configuration), a carrier may also have acquisition signaling or
control signaling that coordinates operations for other
carriers.
Physical channels may be multiplexed on a carrier according to
various techniques. A physical control channel and a physical data
channel may be multiplexed on a downlink carrier, for example,
using time division multiplexing (TDM) techniques, frequency
division multiplexing (FDM) techniques, or hybrid TDM-FDM
techniques. In some examples, control information transmitted in a
physical control channel may be distributed between different
control regions in a cascaded manner (e.g., between a common
control region or common search space and one or more UE-specific
control regions or UE-specific search spaces).
A carrier may be associated with a particular bandwidth of the
radio frequency spectrum, and in some examples the carrier
bandwidth may be referred to as a "system bandwidth" of the carrier
or the wireless communications system 100. For example, the carrier
bandwidth may be one of a number of predetermined bandwidths for
carriers of a particular radio access technology (e.g., 1.4, 3, 5,
10, 15, 20, 40, or 80 MHz). In some examples, each served UE 115
may be configured for operating over portions or all of the carrier
bandwidth. In other examples, some UEs 115 may be configured for
operation using a narrowband protocol type that is associated with
a predefined portion or range (e.g., set of subcarriers or RBs)
within a carrier (e.g., "in-band" deployment of a narrowband
protocol type).
In a system employing MCM techniques, a resource element may
consist of one symbol period (e.g., a duration of one modulation
symbol) and one subcarrier, where the symbol period and subcarrier
spacing are inversely related. The number of bits carried by each
resource element may depend on the modulation scheme (e.g., the
order of the modulation scheme). Thus, the more resource elements
that a UE 115 receives and the higher the order of the modulation
scheme, the higher the data rate may be for the UE 115. In MIMO
systems, a wireless communications resource may refer to a
combination of a radio frequency spectrum resource, a time
resource, and a spatial resource (e.g., spatial layers), and the
use of multiple spatial layers may further increase the data rate
for communications with a UE 115.
Devices of the wireless communications system 100 (e.g., base
stations 105 or UEs 115) may have a hardware configuration that
supports communications over a particular carrier bandwidth, or may
be configurable to support communications over one of a set of
carrier bandwidths. In some examples, the wireless communications
system 100 may include base stations 105 and/or UEs 115 that
support simultaneous communications via carriers associated with
more than one different carrier bandwidth.
Wireless communications system 100 may support communication with a
UE 115 on multiple cells or carriers, a feature which may be
referred to as carrier aggregation or multi-carrier operation. A UE
115 may be configured with multiple downlink component carriers and
one or more uplink component carriers according to a carrier
aggregation configuration. Carrier aggregation may be used with
both FDD and TDD component carriers.
In some cases, wireless communications system 100 may utilize
enhanced component carriers (eCCs). An eCC may be characterized by
one or more features including wider carrier or frequency channel
bandwidth, shorter symbol duration, shorter TTI duration, or
modified control channel configuration. In some cases, an eCC may
be associated with a carrier aggregation configuration or a dual
connectivity configuration (e.g., when multiple serving cells have
a suboptimal or non-ideal backhaul link). An eCC may also be
configured for use in unlicensed spectrum or shared spectrum (e.g.,
where more than one operator is allowed to use the spectrum). An
eCC characterized by wide carrier bandwidth may include one or more
segments that may be utilized by UEs 115 that are not capable of
monitoring the whole carrier bandwidth or are otherwise configured
to use a limited carrier bandwidth (e.g., to conserve power).
In some cases, an eCC may utilize a different symbol duration than
other component carriers, which may include use of a reduced symbol
duration as compared with symbol durations of the other component
carriers. A shorter symbol duration may be associated with
increased spacing between adjacent subcarriers. A device, such as a
UE 115 or base station 105, utilizing eCCs may transmit wideband
signals (e.g., according to frequency channel or carrier bandwidths
of 20, 40, 60, 80 MHz, etc.) at reduced symbol durations (e.g.,
16.67 microseconds). A TTI in eCC may consist of one or multiple
symbol periods. In some cases, the TTI duration (that is, the
number of symbol periods in a TTI) may be variable.
Wireless communications system 100 may be an NR system that may
utilize any combination of licensed, shared, and unlicensed
spectrum bands, among others. The flexibility of eCC symbol
duration and subcarrier spacing may allow for the use of eCC across
multiple spectrums. In some examples, NR shared spectrum may
increase spectrum utilization and spectral efficiency, specifically
through dynamic vertical (e.g., across the frequency domain) and
horizontal (e.g., across the time domain) sharing of resources.
In some cases, a UE 115 may perform a random access procedure with
a network access device (e.g., a base station 105). A UE 115 may
perform a random access procedure with a base station 105 of the
wireless communications system 100, for example, when initially
accessing the wireless network from an idle state (e.g., when
performing initial access from an RRC_IDLE state), or when
performing an RRC Connection Re-establishment procedure, or in
conjunction with a handover procedure. Additionally or
alternatively, the UE 115 may perform a random access procedure
with the base station 105 upon downlink data arrival when in an
RRC_CONNECTED state (e.g., when uplink synchronization is
"non-synchronized"), or upon uplink data arrival when in an
RRC_CONNECTED state (e.g., when uplink synchronization is
"non-synchronized," or when no physical uplink control channel
(PUCCH) resources are available for transmitting a SR). Further
additionally or alternatively, the UE 115 may perform a random
access procedure with the base station 105 for a positioning
purpose when in an RRC_CONNECTED state (e.g., when a timing advance
is needed for UE positioning). In some cases, the UE 115 may
perform a random access procedure with the base station 105 in a CA
or dual-connectivity scenario.
Random access procedures may be contention-based or
non-contention-based. Contention-based random access procedures
may, for example, include random access procedures performed when
initially accessing a communications network from an idle state.
Non-contention-based random access procedures may include, for
example, random access procedures performed in conjunction with a
handover procedure.
According to the techniques described herein, a UE 115 may transmit
a random access request message preamble (e.g., to a base station
105) and receive a random access response message (e.g., from the
base station 105) that indicates multiple uplink grants associated
with the random access request message. Each of the uplink grants
may be associated with different transmission resources (e.g.,
different sets of time, frequency, and/or spatial resources), so
that communications using the assigned resources of different
uplink grants do not collide. The UE 115 may process the random
access response message and, for example, select an uplink grant
from the plurality of uplink grants to transmit a configuration
message (e.g., the RRC connection request message, or Msg3) to the
base station 105 using the corresponding resources.
As similarly described herein, one message of the random access
procedure that is not communicated successfully due to a collision
may cause the random access procedure to fail. For example, if a
first random access procedure fails due to a collision with an RRC
connection request message (e.g., allocated to be transmitted
according to a single uplink grant), or an LBT procedure indicates
that the resources allocated for the RRC connection request message
are not available, the UE 115 and the base station 105 may then
perform a second random access procedure after having used power
and transmission resources to successfully communicate the first
random access request message and the first random access response
message, as well as the failed RRC connection request message.
Further, while the second random access procedure is then performed
successfully, the UE 115 will incur a time delay before
successfully obtaining access to the wireless network.
If, however, multiple uplink grants are configured to allocate
multiple sets of resources for the RRC connection request message
(e.g., according to multiple grants received from the base station
105 and/or as implicitly derived at the UE 115), the UE 115 may
additionally or alternatively transmit the RRC connection request
message using a set of resources that would avoid and/or mitigate
such a collision. For example, according to grant multiplicity
information signaled to the UE 115 in the random access response
message, the UE 115 may transmit multiple repetitions of the RRC
connection request message to the base station 105. Thus, even if a
first transmitted RRC connection request message collides with
another communication, it is relatively probable that the base
station 105 may successfully receive at least one of the RRC
connection request messages, thus conserving power and subsequent
transmission resources (e.g., in time, frequency, and/or space),
for example, as compared to starting a second channel access
procedure upon the failed communication of one RRC connection
request message. Similarly, the UE 115 may not incur a delay (e.g.,
as may have been incurred to perform a second channel access
procedure) before obtaining access to the wireless network and
communicating with the base station 105.
Additionally or alternatively, according to the techniques
described herein, the UE 115 may perform one or more channel access
procedures (e.g., LBT procedures) for each set of resources
allocated for the RRC connection request messages. In this case,
one LBT procedure may indicate that one set of resources is not
available (e.g., on which the RRC connection request message may
encounter a collision), and the UE 115 may transmit one or more RRC
connection request messages using one or more of the sets of
resources for which the UE 115 may have performed a successful LBT
procedure indicating that the corresponding resources are
available. Accordingly, the UE 115 may avoid a potential collision
and successfully communicate the RRC connection request message to
the base station 105, which may allow the UE 115 to conserve power
and subsequent transmission resources. The UE 115 may also avoid an
additional delay that may have been incurred to perform a second
channel access procedure to obtain access to the wireless network,
thus, in some cases, facilitating relatively faster access to the
wireless network after beginning the first channel access
procedure.
FIG. 2 illustrates an example of a wireless communications system
200 that supports techniques for using multiple sets of uplink
resources in a random access procedure in accordance with aspects
of the present disclosure. In some examples, the wireless
communications system 200 may implement aspects of the wireless
communications system 100 as described with reference to FIG. 1.
The wireless communications system 200 includes a base station
105-a and a UE 115-a, which may be examples of the corresponding
devices as described with reference to FIG. 1.
In some such cases, the UE 115-a and the base station 105-a may
perform a random access procedure to establish a connection to be
used to communicate uplink and downlink data transmissions. The
random access procedure may include the UE 115-a transmitting to
the base station 105-a a first message (e.g., Msg1), for example, a
random access request message 205. In response, the base station
105-a may transmit to the UE 115-a a second message (e.g., Msg2),
for example, a random access response message 210. The UE 115-a may
then transmit to the base station 105-a a third message (e.g.,
Msg3), for example, an RRC message referred to as an RRC connection
request message 215, requesting a new or reconfigured connection
with the base station 105-a (e.g., an RRC connection request
message). In some cases, the random access procedure may include
the base station 105-a transmitting to the UE 115-a a fourth
message (e.g., Msg4) including, for example, a contention
resolution message, or other downlink signaling, such as an RRC
connection request message to confirm the requested new or
reconfigured connection. After successfully performing the random
access procedure, the UE 115-a and the base station 105-a may
establish a data connection for subsequent transmissions of data
and other communications.
In some cases, as contemplated herein, the UE 115-a and the base
station 105-a may operate in a shared or unlicensed radio frequency
spectrum bandwidth. In some such cases, before establishing and
initiating communications, the UE 115-a and/or the base station
105-a may utilize a channel access procedure to determine whether
the time and frequency resources for the channel are available,
which may prevent interference and collisions with communications
between another UE 115 and the base station 105-a, another UE 115
and another base station 105, higher priority transmissions (e.g.,
radar), etc. For example, before one or more (e.g., each) of the
messages of the random access procedure, the UE 115-a and/or the
base station 105-a may perform an opportunistic contention-based
channel access procedure (e.g., a LBT procedure, such as a CAT4,
CAT2, or CAT1 LBT procedure, etc.) to contend for access to the
transmission medium or channel. In some cases, the UE 115-a may
perform a directional LBT procedure in multiple transmission
direction, for example, for communications systems using relatively
more directional communications (e.g., mmW communications
systems).
For example, at the beginning of a random access procedure, the UE
115-a may perform an LBT procedure to ascertain that a set of
resources is available for transmission (e.g., time, frequency,
and/or spatial resources allocated for PRACH transmissions). If the
LBT procedure is successful, the UE 115-a may transmit the first
message of a random access procedure including the random access
request message 205 to the base station 105-a. The random access
request message 205 may be, for example, a PRACH transmission
transmitted using a set of resources allocated for PRACH
transmissions. In some cases, the random access request message 205
may include a preamble, for example, selected from a set of
preamble sequences, such as a set of a number (e.g., 64) of
preamble sequences associated with a cell. The UE 115-a may
identify the plurality of preamble sequences from system
information (SI), for example, broadcasted by the base station
105-a.
If the base station 105-a successfully receives the random access
request message 205, the base station 105-a may perform an LBT
procedure for transmitting the second message of the random access
procedure to the UE 115-a. If the LBT procedure is successful, the
base station 105-a may transmit the random access response message
210 to the UE 115-a using, for example, a physical downlink control
channel (PDCCH) and a payload in a physical downlink shared channel
(PDSCH). For example, the base station 105-a may transmit control
information using the PDCCH, and the PDSCH payload may include the
random access response message 210. In some cases, the random
access response message 210 may be transmitted on the PDSCH with a
random access radio network temporary identifier (RA-RNTI) as a
physical identifier. If the base station 105-a does not detect the
random access preamble, or the LBT procedure is unsuccessful, the
base station 105-a may not transmit the random access response
message 210.
The random access response message 210 may include, for example, an
index corresponding to the detected random access preamble of the
UE 115-a (e.g., an index of a detected preamble sequence, such as a
RAPID), an uplink grant (e.g., a grant of time, frequency, and/or
spatial resources using a physical uplink shared channel (PUSCH), a
temporary cell RNTI (TC-RNTI), and other information, such as an
indication of a timing advance (e.g., a timing advance group
(TAG)), etc. In the time domain, the uplink grant may indicate, for
example, a slot offset, a starting symbol and a length of symbols,
and the like. In some examples, the base station 105-a may include
uplink grants in a single payload (e.g., indications of uplink
grants in multiple random access response messages 210
corresponding to different random access preambles received from
different UEs 115).
The UE 115-a may receive the random access response message 210 and
may then determine whether the random access response message 210
contains information intended for the UE 115-a (e.g., rather than
information for other UEs 115 performing other respective random
access procedures). For example, the UE 115-a may monitor a search
space (e.g., a Type-1-Common-PDCCH search space) for the RA-RNTI
corresponding to its transmitted random access request message 205.
In the payload, the UE 115-a may look for a RAPID similarly
corresponding to its transmitted random access request message
205.
If the UE 115-a successfully receives the random access response
message 210, the UE 115-a may perform a further LBT procedure for
transmitting the third message of the random access procedure to
the base station 105-a. If the LBT procedure is successful, the UE
115-a may transmit a first scheduled uplink transmission (e.g., the
RRC connection request message 215) using the transmission
resources associated with an uplink grant included in the random
access response message 210 intended for the UE 115-a. The RRC
connection request message 215 may indicate a configuration for
establishing a communication link, for example, including an RRC
Connection Request message and an identifier of the UE 115-a (i.e.,
a UE-specific identifier). The RRC connection request message 215
may provide a configuration to then establish a communication link
between the UE 115-a and the base station 105-a. The UE 115-a may
scramble the RRC connection request message 215 with the TC-RNTI as
the base station 105-a may have signaled in the random access
response message 210 intended for the UE 115-a.
In some cases, in response to decoding the RRC connection request
message 215, the base station 105-a may further transmit a fourth
message of the random access procedure to the UE 115-a, for
example, a contention resolution message. In some cases, the base
station 105-a may perform a further LBT procedure for the fourth
message. In some examples, the contention resolution message may be
transmitted on the PDSCH, and may be scrambled using the same
TC-RNTI used to scramble the RRC connection request message 215. In
some case, the contention resolution message may include, for
example, the UE identifier received in the RRC connection request
message 215 and/or other information for contention resolution.
Following the successful performance of the random access
procedure, the UE 115-a and the base station 105-a may establish a
communication link to communicate uplink and/or downlink
transmissions, for example, based on the RRC connection request
message 215 (e.g., according to an RRC configuration signaled in
the RRC connection request message 215). In some cases, the base
station 105-a and the UE 115-a may establish the communication link
without communicating the contention resolution message--that is,
the UE 115-a and the base station 105-a may successfully complete
the random access procedure and establish the communication link
when the base station 105-b receives the RRC connection request
message 215.
In some cases, a failed result of an LBT procedure at any stage of
the random access procedure may dictate that the UE 115-a and the
base station 105-a restart from the beginning of a new random
access procedure. In such cases, due to the timing of the messages
of the random access procedure, some resources may end up being
unused. Additionally, in cases of directional LBT, LBT rules may
indicate that transmissions are blocked in certain beam directions,
but transmissions would be permitted in other beam directions. If,
for example, the UE 115-a does not transmit the RRC connection
request message 215 due to a failed LBT procedure during the random
access procedure, the resources allocated for the RRC connection
request message 215 may go unused, thus leading to inefficiencies
in resource utilization.
The UE 115-a and the base station 105-a may utilize multiple sets
of uplink resources to mitigate the effects of and/or prevent such
a failed LBT procedure. In some cases, the base station 105-a may
convey multiple uplink grants to the UE 115-a so that if the medium
is busy during the resources of a first uplink grant, the UE 115-a
may transmit the RRC connection request message 215 using resources
of one or more additional uplink grants. For example, the base
station 105-a may indicate multiple sets of uplink resources in a
payload of a single random access response message 210.
Additionally or alternatively, the base station 105-a may configure
each of multiple uplink grants separately in separate random access
response message payloads. As further described with reference to
FIGS. 3 and 4, one or more random access response message payloads
may, for example, include a common TC-RNTI for one or more of the
grants, a common RAPID for one or more of the grants, and/or
multiple different RAPIDs between one or more of the grants (e.g.,
for multi-beam grants in directional communications). Additionally
or alternatively, as further described with reference to FIG. 5,
the base station 105-a may indicate a grant for one set of uplink
resources in the random access response message 210, and the UE
115-a may derive further grants implicitly from the first uplink
grant.
When the UE 115-a identifies multiple sets of resources to be used
for transmitting the RRC connection request message 215 (e.g.,
according to multiple uplink grants), the UE 115-a may, in some
cases, transmit the RRC connection request message 215 using the
resources allocated by more than one of the uplink grants (e.g.,
using the resources of each of the uplink grants). Alternatively,
the UE 115-a may transmit the RRC connection request message 215
using the resources allocated by only one of the uplink grants. For
example, the UE 115-a may use the grant corresponding to the
earliest time resources, a first of the uplink grants for which the
UE 115-a successfully performs an LBT procedure, and/or, when beam
indications are present for directional communications, using a
strongest downlink SSB of the SSBs indicated via the RAPIDs and/or
via SSB indexes.
That is, for directional communications using different directional
transmit beams, the UE 115-a may receive beam information in the
random access response message 210 indicating one or more beams to
be used for transmitting the RRC connection request message 215.
The UE 115-a may identify one or more uplink beams to be used to
transmit the RRC connection request message 215 according to a beam
correspondence based on the random access response message 210
(e.g., a known correspondence between uplink and downlink beams).
For example, the UE 115-a may identify a particular beam according
to the beam indexes corresponding to indicated RAPIDs). For
example, the UE 115-a may identify a particular beam with
particular beam parameters (e.g., a direction, etc.) to be used to
transmit the RRC connection request message 215. In some cases, the
UE 115-a may perform a directional LBT procedure according to a
beam correspondence (i.e., a correspondence between particular
uplink and downlink, or transmit and receive, beams), and the
directional LBT procedure may accordingly indicate that the medium
is available in some directions but busy in other directions. In
some cases, the UE 115-a may derive beam indexes according to the
uplink grant to be used to transmit the RRC connection request
message 215 and/or to perform an LBT procedure where the derived
beam index does not correspond to a beam that the UE 115-a used to
transmit the random access request message 205.
For directional communications using one or more directional
transmit and/or receive beams, the base station 105-a may include
beam information in the random access response message 210
indicating one or more beams to be used for transmitting the RRC
connection request message 215. For example, as further described
with reference to FIGS. 6 and 7, the base station 105-a may
indicate one or more SSBs to be used for transmitting the RRC
connection request message 215 according to one or more SSB indexes
(e.g., by includes an explicit SSB index (SSBIdx) and/or channel
state information (CSI) reference signal (CSI-RS) index (CSIRSidx)
in the random access response message payload), one or more RAPIDs,
and the like. As such, the UE 115-a and the base station 105-a may
map each preamble of one or more random access request messages 205
to a corresponding SSB index or group of SSB indexes, and an index
of the preambles may map to corresponding RAPIDs, such that the
base station 105-a may use the RAPIDs to identify particular beams
or sets of beams with particular beam parameters to be used to
transmit the RRC connection request message 215. In this way, the
base station 105-a may identify a particular beam via its
corresponding RAPID even though the UE 115-a did not transmit the
random access request message 205 using the corresponding RAPID. In
some cases, the base station 105-a may signal multiple RAPIDs using
one grant in a random access response message payload.
Alternatively, the base station 105-a may signal multiple RAPIDs
using multiple grants in a random access response message payload
(e.g., using one RAPID per grant).
In some cases, the base station 105-a may include information in
the random access response message 210 indicating one or more
channel access procedure parameters. For example, the channel
access procedure parameters may include a channel access priority
parameter, a channel occupancy time (COT) parameter, and other
information that the UE 115-a may use to perform subsequent LBT
operations. For example, before transmitting the RRC connection
request message 215 using one or more sets of resources (e.g.,
according to one or more corresponding uplink grants received from
the base station 105-a), the UE 115-a may perform one or more LBT
operations according to the channel access procedure parameters for
each of the respective sets of resources. The UE 115-a may perform
the LBT operations according to a channel access priority as
signaled in the channel access procedure parameters and/or perform
the LBT operations using a duration according to the COT parameter
as signaled in the channel access procedure parameters.
Additionally or alternatively, the UE 115-a may apply the channel
access procedure parameters to a directional LBT operation to be
performed before transmitting using one or more directional
transmit beams.
In some cases, the UE 115-a may scale and/or time-shift the RRC
connection request message 215 according to timing information
included in the random access response message. For example, as
similarly described herein, an uplink grant may indicate an offset
given k2+A, where k2 is a configurable slot offset parameter (e.g.,
a range of 4 values each separated by 1 slot), and .DELTA. is an
length of time to be applied as the offset. After receiving the
random access response message 210 in a slot allocated for a PDSCH,
the UE 115-a may wait for a duration of the offset before
transmitting the RRC connection request message 215 in a slot
allocated for PUSCH. When the base station 105-a signals multiple
uplink grants and/or multiple sets of resources to be used to
transmit the RRC connection request message 215, the offset
(Offset(i)) may then be given by Offset(i)=k2*Scale(i)+.DELTA., or
Offset(i)=k2*Scale(i)+.DELTA.+.beta.(i), where i is an index of the
ith uplink grant, and Scale(i) and .beta.(i) are scaling and
time-shifting functions, respectively, parametrized according to
the uplink grant index i. Such time offsets may separate the time
resources according for each of the uplink grants, accordingly
increasing LBT diversity at the UE 115-a (i.e., increased diversity
between the different sets of resources for which the UE 115-a may
perform LBT operations). This may, in some cases, relatively
increase the probability that the UE 115-a successfully performs an
LBT procedure according to the uplink grants.
FIG. 3 illustrates an example of a message format 300 for a
communications scheme that supports techniques for using multiple
sets of uplink resources in a random access procedure in accordance
with aspects of the present disclosure. In some examples, the
message format 300 may implement aspects of the wireless
communications systems 100 and 200 as described with reference to
FIGS. 1 and 2. The message format 300 illustrates a conceptual
format for information that to be conveyed in a random access
response message of a random access procedure between a base
station and a UE. The message format 300 illustrates a random
access response message format in which the base station separately
configures one or more uplink grants 310 and other parameters.
The message format 300 shows the format of a payload 305 of a
random access response message (e.g., in a Msg2 of the random
access procedure), as a base station may transmit to a UE. The
payload 305 includes fields for information bits for: multiple
uplink grants 310 (e.g., four uplink grants 310 as shown in FIG. 3,
or any other suitable number of uplink grants 310), multiple random
access preamble identifiers (e.g., RAPIDs 315), multiple temporary
cell identifiers (e.g., TC-RNTIs 320), and multiple fields for
other information 325.
As similarly described with reference to FIG. 2, a UE and a base
station may utilize multiple sets of uplink resources for the UE to
transmit a configuration message (e.g., an RRC connection request
message, for example, in a Msg3 of the random access procedure) to
the base station. In some cases, the base station may convey
multiple uplink grants to the UE, where each uplink grant indicates
an allocated set of time, frequency, and/or spatial resources with
which the UE may transmit an RRC connection request message. In
some cases, the sets of resources indicated in each of the uplink
grants 310 may be, for example, partially or completely
non-overlapping. For example, the base station may indicate
multiple sets of uplink resources in the payload 305 of the random
access response message. Additionally or alternatively, the base
station may configure each of multiple uplink grants separately in
separate random access response message payloads 305, and the base
station may transmit each payload 305 using, for example, a
PDSCH.
Before transmitting the RRC connection request message, the UE may
perform an LBT procedure for one or more of the corresponding sets
of allocated resources indicated in the uplink grants 310. If the
UE determines that the medium is busy during the resources of a
first uplink grant 310 (e.g., according to a first LBT procedure),
the UE may perform one or more further LBT procedures for the
resources indicated by additional uplink grants 310. After
successfully performing one or more LBT procedures for one or more
of the allocated sets of resources, the UE may transmit the RRC
connection request message on the set resources for which the UE
successfully performed the corresponding LBT procedure.
In the example of FIG. 3, the base station may separately (i.e.,
independently) configure each uplink grant 310, identifiers, and
other information. As shown in FIG. 3, the message format 300 shows
a format for a random access response message including separate
fields for separate and different uplink grants 310, separate
fields for different RAPIDs 315, separate fields for different
TC-RNTIs 320, and separate fields for other information 325. Each
field may include one or more bits that signals the respective
information. For example, each uplink grant 310 may include
information bits that indicate a corresponding set of allocated
uplink time, frequency, and/or spatial resources for transmitting
the RRC connection request message.
In some cases, the base station may separately configure the one or
more fields for one or more information bits for each of the RAPIDs
315 corresponding to respective ones of the uplink grants 310. The
RAPIDs 315 may identify the UE as the UE for which the random
access response message is intended via a corresponding preamble
sequence and/or SSB that the UE may have used to transmit a random
access request message (e.g., in a Msg1 of the random access
procedure). The base station may similarly separately configure the
one or more fields for one or more information bits for each of the
TC-RNTIs 320 corresponding to respective ones of the uplink grants
310. The UE may subsequently use the signaled values for the
TC-RNTIs 320 to scramble the RRC connection request message
transmission. The base station may further similarly separately
configure the one or more fields for one or more information bits
for the other information 325 corresponding to respective ones of
the uplink grants 310. The other information 325 may include timing
information, LBT information, and/or the other information as
described herein.
In some cases, each of the fields for each of the RAPIDs 315,
TC-RNTIs 320, and other information 325 may carry the same
information for each respective uplink grant 310 (i.e., each of the
RAPIDs 315 indicating the same values corresponding to the same UE
preamble sequence, etc.). Alternatively, the RAPIDs 315 may have
different values corresponding to different preamble sequences,
and/or the TC-RNTIs 320 may have different values for RRC
connection request message transmissions using one or more of the
different uplink grants 310, and/or the other information 325 may
have different information corresponding to each of the respective
uplink grants 310. The techniques described herein thus provide for
flexible scheduling of the uplink grants 310 such that the base
station may be able to more dynamically account for network
conditions (e.g., due to varying collisions, interference,
etc.).
FIG. 4 illustrates an example of a message format 400 for a
communications scheme that supports techniques for using multiple
sets of uplink resources in a random access procedure in accordance
with aspects of the present disclosure. In some examples, the
message format 400 may implement aspects of the wireless
communications systems 100 and 200 as described with reference to
FIGS. 1 and 2. The message format 400 may, in some cases, implement
aspects of the message format 300 as described with reference to
FIG. 3. The message format 400 illustrates a conceptual format for
information to be conveyed in a random access response message of a
random access procedure between a base station and a UE. The
message format 400 illustrates a random access response message
format in which the base station configures one or more uplink
grants 410 and other parameters with at least some common
information configured for multiple uplink grants 410.
The message format 400 shows the format of a payload 405 of a
random access response message (e.g., in a Msg2 of the random
access procedure), as a base station may transmit to a UE. The
payload 405 includes fields for information bits for: multiple
uplink grants 410 (e.g., four uplink grants 410 as shown in FIG. 4,
or any other suitable number of uplink grants 410), multiple random
access preamble identifiers (e.g., RAPIDs 415), multiple temporary
cell identifiers (e.g., TC-RNTIs 420), and multiple fields for
other information 425.
As similarly described with reference to FIG. 2, a UE and a base
station may utilize multiple sets of uplink resources for the UE to
transmit a configuration message (e.g., an RRC connection request
message, for example, in a Msg3 of the random access procedure) to
the base station. In some cases, the base station may convey
multiple uplink grants to the UE, where each uplink grant indicates
an allocated set of time, frequency, and/or spatial resources with
which the UE may transmit an RRC connection request message. In
some cases, the sets of resources indicated in each of the uplink
grants 410 may be, for example, partially or completely
non-overlapping. For example, the base station may indicate
multiple sets of uplink resources in the payload 405 of the random
access response message. Additionally or alternatively, the base
station may configure each of multiple uplink grants separately in
separate random access response message payloads 405, and the base
station may transmit each payload 405 using, for example, a
PDSCH.
Before transmitting the RRC connection request message, the UE may
perform an LBT procedure for one or more of the corresponding sets
of allocated resources indicated in the uplink grants 410. If the
UE determines that the medium is busy during the resources of a
first uplink grant 410 (e.g., according to a first LBT procedure),
the UE may perform one or more further LBT procedures for the
resources indicated by additional uplink grants 410. After
successfully performing one or more LBT procedures for one or more
of the allocated sets of resources, the UE may transmit the RRC
connection request message on the set resources for which the UE
successfully performed the corresponding LBT procedure.
In the example of FIG. 4, the base station may separately (i.e.,
independently) configure each uplink grant 410 and commonly (i.e.,
jointly) configure identifiers and/or other information. As shown
in FIG. 4, the message format 400 shows a format for a random
access response message including separate fields for different
uplink grants 410, a common field for a RAPID 415, a common field
for a TC-RNTI 420, and separate fields for other information 425.
Each field may include one or more bits that signals the respective
information. For example, each uplink grant 410 may include
information bits that indicate a corresponding set of allocated
uplink time, frequency, and/or spatial resources for transmitting
the RRC connection request message.
In some cases, the base station may commonly configure one or more
field for one or more information bits for the RAPID 415. That is,
base station may configure the same RAPID 415 for each of the
uplink grants 410. The RAPID 415 may identify the UE as the UE for
which the random access response message is intended via a
corresponding preamble sequence and/or SSB that the UE may have
used to transmit a random access request message (e.g., in a Msg1
of the random access procedure). As shown in FIG. 4, the base
station may similarly commonly configure one or more fields for one
or more information bits for the TC-RNTI 420 applicable for each of
the uplink grants 410. The UE may subsequently use the signaled
values for the TC-RNTI 420 to scramble the RRC connection request
message transmission. Though not shown in FIG. 4, in other cases,
the base station may configure a common RAPID 415, but multiple
different TC-RNTIs 420 to be used to transmit RRC connection
request messages corresponding to different uplink grants 410. The
base station may further similarly commonly configure the one or
more fields for one or more information bits for the other
information 425 corresponding to respective ones of the uplink
grants 410. The other information 425 may include timing
information, LBT information, and/or the other information as
described herein.
In some cases, the base station may further configure grant
multiplicity information to be signaled as part of the payload 405.
The configure grant multiplicity information may include one or
more grant multiplicity parameters to the UE using the other
information 425. The grant multiplicity parameter may indicate a
number of repetitions for the UE to transmit the RRC connection
request message (among other information for such repetitions). For
example, the grant multiplicity information may indicate that the
UE transmit four repetitions of the RRC connection request message
(providing for relatively improved reliability, e.g., in situations
in which the probability of a collision may be relatively
higher).
In some cases, in combination with any of the techniques described
herein, the base station may configure time or frequency resources
to be in common between multiple of the uplink grants 410 (e.g.,
configuring a same set of time or frequency resources for each of
the uplink grants 410). For example, the base station may configure
each of the uplink grants 410 to indicate an allocation of the same
set of frequency resources, and vary time resources between
different uplink grants 410. Alternatively, the base station may
configure each of the uplink grants 410 to indicate an allocation
of the same set of time resources, and vary frequency resources
between different uplink grants 410. Signaling more of the values
and parameters in the payload 405 using common parameters may, in
some cases, provide for relatively lower transmission smaller and
thus relatively lower signaling complexity.
FIG. 5 illustrates an example of a message format 500 for a
communications scheme that supports techniques for using multiple
sets of uplink resources in a random access procedure in accordance
with aspects of the present disclosure. In some examples, the
message format 500 may implement aspects of the wireless
communications systems 100 and 200 as described with reference to
FIGS. 1 and 2. The message format 500 may, in some cases, implement
aspects of the message formats 300 and 400 as described with
reference to FIGS. 3 and 4. The message format 500 illustrates a
conceptual format for information to be conveyed in a random access
response message of a random access procedure between a base
station and a UE. The message format 500 illustrates a random
access response message format based on which the UE may implicitly
derive additional grants.
The message format 500 shows the format of a payload 505 of a
random access response message (e.g., in a Msg2 of the random
access procedure), as a base station may transmit to a UE. The
payload 505 includes fields for information bits for: an uplink
grant 510, a random access preamble identifier (e.g., a RAPID 515),
a temporary cell identifier (e.g., a TC-RNTIs 520), and one set of
fields for other information 525.
In some cases, a UE and a base station may utilize multiple sets of
uplink resources for the UE to transmit a configuration message
(e.g., an RRC connection request message, for example, in a Msg3 of
the random access procedure) to the base station. In some cases,
the base station may indicate one uplink grant 510 (or,
alternatively, multiple uplink grants 510) for one set of uplink
resources in the random access response message, and the UE may
derive one or more additional grants implicitly from the first
uplink grant 510 (e.g., internally at the UE).
Before transmitting the RRC connection request message, the UE may
perform an LBT procedure using the set of allocated resources
indicated in the uplink grant 510. If the UE determines that the
medium is busy during the resources of a first uplink grant (e.g.,
according to a first LBT procedure), the UE may perform one or more
further LBT procedures for the resources defined by the one or more
additional grants that the UE may derive. After successfully
performing one or more LBT procedures for one or more of the
allocated sets of resources, the UE may transmit the RRC connection
request message on the set resources for which the UE successfully
performed the corresponding LBT procedure.
In the example of FIG. 5, the base station may configure the uplink
grant 510 and the identifiers and/or other information signaled in
the payload 505. As shown in FIG. 5, the message format 500 shows a
format for a random access response message including separate
fields for the uplink grants 510, the RAPID 515, the TC-RNTI 520,
and for other information 525. Each field may include one or more
bits that signals the respective information. For example, the
uplink grant 510 may include information bits that indicate a
corresponding set of allocated uplink time, frequency, and/or
spatial resources for transmitting the RRC connection request
message.
In some cases, based on the uplink grant 510 received from the base
station in the random access procedure payload 505, the UE may
implicitly derive additional grants of uplink resources (e.g.,
time, frequency, and/or spatial resources) that the UE may then use
to transmit the RRC connection request message. For example, an
implicit rule may be defined according to a multiple grant
configuration for a wireless communications system including the UE
and the base station based on which the UE is configured to
operate. In some cases, the UE may perform operations to derive
additional grants according to the multiple grant configuration. In
some cases, the multiple grant configuration may be signaled to the
UE via a separate instance of received signaling (e.g., an RRC
configuration signaled in a remaining system information (RMSI)
transmission, dedicated RRC signaling in a contention-free random
access procedure, etc.). The multiple grant configuration may
include parameters indicating, for example, a maximum number of
grants that the UE is to derive, a relationship between the
resources of the signaled uplink grant 510 and the grants that the
UE is to derive (e.g., an overlap, increase, decrease, and the
like, in the frequency or time resources for the derived grant),
and/or a modulation and coding scheme (MCS) to be used for the
signaled uplink grant 510 and the grants that the UE is to derive
(e.g., using an identical MCS for the derived grants as the
signaled uplink grant 510). In some cases, the UE may derive
additional grants based on multiple received uplink grants 510, for
example, to generate more sets of resources on which to transmit
the RRC connection request message. After deriving the additional
grants, the UE may proceed as otherwise described herein (e.g.,
successfully performing an LBT for one of the derived grants,
transmitting the RRC connection request message to the base station
using that grant, and so on).
FIG. 6 illustrates an example of a message format 600 for a
communications scheme that supports techniques for using multiple
sets of uplink resources in a random access procedure in accordance
with aspects of the present disclosure. In some examples, the
message format 600 may implement aspects of the wireless
communications systems 100 and 200 as described with reference to
FIGS. 1 and 2. The message format 600 may, in some cases, implement
aspects of the message formats 300, 400, and 500 as described with
reference to FIGS. 3 through 5. The message format 600 illustrates
a conceptual format for information to be conveyed in a random
access response message of a random access procedure between a base
station and a UE. The message format 600 illustrates a random
access response message format for communicating beam information
for directional communications based on a signaled SSB index.
In the example of FIG. 6, the UE may transmit and receive
directional communications using one or more directional transmit
and/or receive beams. The message format 600 shows the format of a
payload 605 of a random access response message (e.g., in a Msg2 of
the random access procedure), as a base station may transmit to a
UE. The payload 605 includes fields for information bits for: one
or more uplink grants 610, a random access preamble identifier
(e.g., a RAPID 615), a temporary cell identifier (e.g., a TC-RNTIs
620), a set of fields for other information 625. In the example of
the message format 600, the payload 605 further includes one or
more fields for one or more information bits for beam information
630, the beam information including, for example, an SSB index
and/or an SSB group (i.e., a group of individual SSB indexes) to be
used for determining directional transmit beams.
In some cases, a UE and a base station may utilize multiple sets of
uplink resources for the UE to transmit a configuration message
(e.g., an RRC connection request message, for example, in a Msg3 of
the random access procedure) to the base station. As described
herein, in some cases, the base station may convey multiple uplink
grants to the UE, where each uplink grant indicates an allocated
set of time, frequency, and/or spatial resources with which the UE
may transmit an RRC connection request message. Additionally or
alternatively, as also described herein, the base station may
indicate one or more uplink grants 610 based on which the UE may
implicitly derive one or more additional grants from the first
uplink grant 610.
Before transmitting the RRC connection request message, the UE may
perform an LBT procedure using the set of allocated resources
indicated in the uplink grants 610. In some cases, the LBT
procedure may be a directional LBT procedure in which the UE may
listen in multiple transmission direction to determine whether the
medium is available for a particular directional beam. If the UE
determines that the medium is busy during the resources of a first
uplink grant (e.g., according to a first LBT procedure), the UE may
perform one or more further LBT procedures (e.g., in one or more
additional directions) for the resources defined by the uplink
grants 610. The directional LBT procedure may indicate that the
medium is available in some directions but busy in other
directions. After successfully performing one or more LBT
procedures using a certain beam for one or more of the allocated
sets of resources, the UE may transmit the RRC connection request
message on the set resources for which the UE successfully
performed the corresponding LBT procedure (including, e.g., using a
directional beam for which the corresponding LBT procedure was
successful).
For directional communications using different directional transmit
beams, as similarly described herein, the base station may include
beam information 630 in the random access response message payload
605. The beam information 630 may, for example, directly indicate
beam parameters for one or more directional beams to be used for
transmitting the RRC connection request message (e.g., a transmit
direction, a transmit power, etc.). As shown in FIG. 6, the base
station may indicate in the beam information 630 one or more
explicit indications of one or more SSBs for the UE to use to
transmit the RRC connection request message. For example, the beam
information 630 may indicate an SSB index corresponding to an SSB
group for transmission.
Based on the beam information 630, the UE may determine one or more
uplink beams to be used to transmit the RRC connection request
message according to a beam correspondence (e.g., a correspondence
between uplink and downlink beams and/or to indexes and the
corresponding communications). For example, the UE may identify a
particular beam with particular beam parameters (e.g., a direction,
transmit power, etc.) to be used to transmit the RRC connection
request message. The UE may then transmit the RRC connection
request message according using a directional beam according to the
beam information 630 for which the UE successfully performed a
directional LBT procedure (e.g., according to the explicit SSB
index and SSB group included in the beam information 630).
FIG. 7 illustrates an example of a message format 700 for a
communications scheme that supports techniques for using multiple
sets of uplink resources in a random access procedure in accordance
with aspects of the present disclosure. In some examples, the
message format 700 may implement aspects of the wireless
communications systems 100 and 200 as described with reference to
FIGS. 1 and 2. The message format 700 may, in some cases, implement
aspects of the message formats 300, 400, 500, and 600 as described
with reference to FIGS. 3 through 6. The message format 700
illustrates a conceptual format for information to be conveyed in a
random access response message of a random access procedure between
a base station and a UE. The message format 700 illustrates a
random access response message format for communicating beam
information for directional communications based on a signaled
RAPID 715.
In the example of FIG. 7, the UE may transmit and receive
directional communications using one or more directional transmit
and/or receive beams. The message format 700 shows the format of a
payload 705 of a random access response message (e.g., in a Msg2 of
the random access procedure), as a base station may transmit to a
UE. The payload 705 includes fields for information bits for: one
or more uplink grants 710, a random access preamble identifier
(e.g., a RAPID 715), a temporary cell identifier (e.g., a TC-RNTIs
720), a set of fields for other information 725. In the example of
the message format 700, the payload 705 further includes one or
more fields for one or more information bits for beam information
730, the beam information including, for example, a list of RAPIDs
to be used for determining directional transmit beams.
In some cases, a UE and a base station may utilize multiple sets of
uplink resources for the UE to transmit a configuration message
(e.g., an RRC connection request message, for example, in a Msg3 of
the random access procedure) to the base station. As described
herein, in some cases, the base station may convey multiple uplink
grants to the UE, where each uplink grant indicates an allocated
set of time, frequency, and/or spatial resources with which the UE
may transmit an RRC connection request message. Additionally or
alternatively, as also described herein, the base station may
indicate one or more uplink grants 710 based on which the UE may
implicitly derive one or more additional grants from the first
uplink grant 710.
Before transmitting the RRC connection request message, the UE may
perform an LBT procedure using the set of allocated resources
indicated in the uplink grants 710. In some cases, the LBT
procedure may be a directional LBT procedure in which the UE may
listen in multiple transmission direction to determine whether the
medium is available for a particular directional beam. If the UE
determines that the medium is busy during the resources of a first
uplink grant (e.g., according to a first LBT procedure), the UE may
perform one or more further LBT procedures (e.g., in one or more
additional directions) for the resources defined by the uplink
grants 710. The directional LBT procedure may indicate that the
medium is available in some directions but busy in other
directions. After successfully performing one or more LBT
procedures using a certain beam for one or more of the allocated
sets of resources, the UE may transmit the RRC connection request
message on the set resources for which the UE successfully
performed the corresponding LBT procedure (including, e.g., using a
directional beam for which the corresponding LBT procedure was
successful).
For directional communications using different directional transmit
beams, as similarly described herein, the base station may include
beam information 730 in the random access response message payload
705. The beam information 730 may include information based on
which the UE may determine beam parameters for one or more
directional beams to be used for transmitting the RRC connection
request message (e.g., a transmit direction, a transmit power,
etc.). As shown in FIG. 7, the base station may indicate in the
beam information 730 a list of RAPIDs corresponding to one or more
random access preambles (e.g., as the UE may use to transmit random
access request messages).
In some cases, the UE may derive beam indexes to be used to
transmit the RRC connection request message according to the
information included in the random access response message payload
705. Based on the beam information 730, the UE may determine one or
more uplink beams to be used to transmit the RRC connection request
message according to a beam correspondence between the RAPIDs of
the list of RAPIDs indicated in the beam information and indexes or
parameters of particular transmit beams. For example, the base
station and UE may map each preamble of one or more random access
request messages to a corresponding SSB index or group of SSB
indexes, and an index of the preambles may map to corresponding
RAPIDs. Through this correspondence, the base and the UE station
may identify a particular transmit beam to the UE based on the list
of RAPIDs in the beam information 730. In this way, in some cases,
the base station identify a transmit beam via its corresponding
RAPID even though the UE did not transmit the random access request
message using the corresponding RAPID.
The UE may correspondingly determine beam parameters for one or
more transmit beams for one or more subsequent RRC connection
request messages using one or more beams corresponding to the
respective RAPIDs received in the list of RAPIDs. For example, the
UE may identify a beam with particular beam parameters (e.g., a
direction, transmit power, etc.) to be used to transmit the RRC
connection request message based on the beam parameters
corresponding to those mapped to a certain RAPID preamble.
In some cases, the UE may use determine a signal strength
associated with each of the transmit beams indicated via the list
of RAPIDs, and the UE may determine to transmit one or more RRC
connection request messages using a transmit beam for which the UE
determined to have a strongest signal strength (or the multiple
transmit beams with the strongest signal strengths). The UE may
then transmit the RRC connection request message using the
directional beam or beams accordingly.
FIG. 8 illustrates an example of a process flow 800 that supports
techniques for using multiple sets of uplink resources in a random
access procedure in accordance with aspects of the present
disclosure. In some examples, the process flow 800 may implement
aspects of the wireless communications system, as described with
reference to FIG. 1 through 7. The process flow 800 shows an
example of communications between a base station 105-b and a UE
115-b, which may be examples of the corresponding devices as
described with reference to FIGS. 1 through 7.
At 805, the UE 115-b may transmit to the base station 105-b, and
the base station 105-b may receive from the UE 115-b, a random
access request message. The random access request message may be,
for example, a PRACH transmission transmitted using a set of
resources allocated for PRACH transmissions. In some cases, the
random access request message may include a preamble, for example,
selected from a set of preamble sequences, such as a set of
preamble sequences associated with a cell.
At 810, the base station 105-b may identify beam information
associated with the grant for the first set of uplink resources
(e.g., to configure direction transmissions from the UE 115-b using
one of multiple possible uplink transmit beams).
At 815, the base station 105-b may transmit to the UE 115-b, and
the UE 115-b may receive from the base station 105-b, a random
access response message in response to the random access request
message. In some cases, the random access response message may
include a grant for a first set of uplink resources for
transmitting an RRC connection request message (e.g., a Msg3 of a
random access procedure) to the base station 105-b (e.g., at 830).
In some cases, the random access response message may include one
or more additional grants for at least the second set of uplink
resources transmitting the RRC connection request message to the
base station 105-b.
In some cases, the grant and/or the one or more additional grants
may include respective channel access procedure parameters for
accessing the first set of uplink resources or the second set of
uplink resources. In some cases, the channel access procedure
parameters may include a channel access priority, COT information,
or a combination thereof, associated with the corresponding first
set of uplink resources or second set of uplink resources.
In some cases, the random access response message may include
timing information, where the timing information may indicate a
time-domain offset between the random access response message, the
one or more of the first set of uplink resources, the second set of
uplink resources, or a combination thereof. In some cases, the
random access response message may include grant multiplicity
information, the grant multiplicity information indicating a number
of grants to be used for repeating transmission of the RRC
connection request message.
In some cases, for example, for directional communications, the
random access response message may indicate beam information
associated with the grant for the first set of uplink resources,
and beam parameters for an uplink beam (e.g., a transmit beam) to
be used to transmit the RRC connection request message are based on
the beam information. The beam information may indicate a mapping
of one or more beam indexes according to one or more corresponding
random access preamble identifiers. Alternatively, the beam
information may indicate one or more downlink beam parameters for a
downlink beam used to receive synchronization signals from the base
station 105-b, and the UE 115-b may determine the uplink beam to be
used to transmit the RRC connection request message based on a
correspondence between the downlink beam parameters and the uplink
beam parameters (e.g., a transmit-receive beam correspondence). In
some cases, a downlink beam used to receive the synchronization
signals from the base station may be different than a second
downlink beam used to receive the random access response message
from the base station at 815 (e.g., different downlink beams using
different sets of frequency resources). In some cases, the UE 115-b
may determine the uplink beam to be used to transmit the RRC
connection request message to the base station based on the beam
parameters for the uplink beam.
At 820, the UE 115-b may determine at least a second set of uplink
resources for transmitting the RRC connection request message to
the base station based on the grant for the first set of uplink
resources. In some cases, determining at least the second set of
uplink resources may be based on the one or more additional grants
received from the base station 105-b. In some cases, each of the
grant and the one or more additional grants may include a random
access preamble identifier (e.g., a RAPID), and/or a temporary cell
identifier (e.g., a TC-RNTI) for the random access request message
of the UE. In some cases, each of the random access preamble
identifiers and/r the temporary cell identifiers of each of the
grant and the one or more additional grants may have a same value.
Alternatively, in other cases, each of the random access preamble
identifiers and/or the temporary cell identifiers of each of the
grant and the one or more additional grants may have a different
value.
In some cases, the UE 115-a may have previously received a multiple
grant configuration, for example, via a system information block
(SIB) message, an RMSI message, a dedicated signaling message, or a
combination thereof. In some such cases, the UE 115-b may determine
at least the second set of uplink resources for transmitting the
RRC connection request message to the base station 105-b based on
the multiple grant configuration. That is, the UE 115-b may perform
operations to internally derive additional grants according to the
multiple grant configuration. For example, the UE 115-b may
determine at least the second set of uplink resources for
transmitting the RRC connection request message to the base station
105-b based on the multiple grant configuration. The multiple grant
configuration may include parameters indicating, for example, a
maximum number of grants that the UE is to derive, a relationship
between the resources of the signaled uplink grant 510 and the
grants that the UE is to derive (e.g., an overlap, increase,
decrease, and the like, in the frequency or time resources for the
derived grant), and/or an MCS to be used for the signaled uplink
grant 510 and the grants that the UE is to derive (e.g., using an
identical MCS for the derived grants as the signaled uplink grant
510).
At 825, the UE 115-b may perform a channel access procedure (e.g.,
an LBT procedure) for both the first set of uplink resources and
the second set of uplink resources.
The LBT procedure may, for example, prevent interference and
collisions with communications between another UE 115 and the base
station 105-b, another UE 115 and another base station 105, higher
priority transmissions (e.g., radar), etc. In some cases, before
each of the messages of the random access procedure, the UE 115-b
and/or the base station 105-b may perform an LBT procedure to
contend for access to the transmission medium or channel. In some
cases, the UE 115-b may perform a directional LBT procedure in
multiple transmission direction, for example, for communications
systems employing directional transmit and receive beams.
At 830, the UE 115-b may transmit to the base station 105-b, and
the base station 105-b may receive from the UE 115-b, an RRC
connection request message. In some cases, the UE 115-b may
transmit the RRC connection request message using the uplink beam,
as may have been determined based on the beam information received
at 815.
In some case, the UE 115-b may determine a signal strength for
beams used to communicate using each of the first set of uplink
resources and the second set of uplink resources, and the UE 115-b
may transmit the RRC connection request message using whichever of
the first set of uplink resources or the second set of uplink
resources is associated with a greatest signal strength (e.g., an
uplink transmit beam with a strongest signal strength). In some
cases, the UE 115-b may transmit the RRC connection request message
according to the timing information received from the base station
105-b, for example, in the random access response message at 815.
In some cases, the UE 115-b may transmit the RRC connection request
message using whichever of the first set of uplink resources or the
second set of uplink resources has an earliest time component.
In some cases, the UE 115-b may transmit the RRC connection request
message based on a successful result of one or more of the channel
access procedures according to the respective channel access
procedure parameters received with the respective uplink grants at
815. In some cases, the UE 115-b may transmit the RRC connection
request message using whichever of the first set of uplink
resources or the second set of uplink resources corresponds to a
first successful channel access procedure, for example at 825.
In some cases, the UE 115-b may repeat transmission of the RRC
connection request message to the base station using one or more of
the first set of uplink resources or the second set of uplink
resources (e.g., using a number of uplink grants as may have been
configured according to the multiple grant configuration and/or the
grant multiplicity information).
At 835, the base station 105-b may transmit to the UE 115-b, and
the UE 115-b may receive from the base station 105-b, a contention
resolution message, for example, in response to receiving the RRC
connection request message at 830. In some examples, the contention
resolution message may be transmitted on the PDSCH, and may be
scrambled using the same temporary network identifier used to
scramble the RRC connection request message. The contention
resolution message may include, for example, the UE identifier
received in the RRC connection request message 215 and/or other
information for contention resolution
At 840, the UE 115-b and the base station 105-b may establish a
connection based on the RRC connection request message. The UE
115-b and the base station 105-b may use the connection for
subsequent transmissions of data and other communications.
FIG. 9 shows a block diagram 900 of a device 905 that supports
techniques for using multiple sets of uplink resources in a random
access procedure in accordance with aspects of the present
disclosure. The device 905 may be an example of aspects of a UE 115
as described herein. The device 905 may include a receiver 910, a
communications manager 915, and a transmitter 920. The device 905
may also include a processor. Each of these components may be in
communication with one another (e.g., via one or more buses).
The receiver 910 may receive information such as packets, user
data, or control information associated with various information
channels (e.g., control channels, data channels, and information
related to techniques for using multiple sets of uplink resources
in a random access procedure, etc.). Information may be passed on
to other components of the device 905. The receiver 910 may be an
example of aspects of the transceiver 1220 described with reference
to FIG. 12. The receiver 910 may utilize a single antenna or a set
of antennas.
The communications manager 915 may transmit a random access request
message to a base station, receive a random access response message
from the base station in response to the random access request
message, the random access response message including a grant for a
first set of uplink resources for transmitting an RRC connection
request message to the base station, determine at least a second
set of uplink resources for transmitting the RRC connection request
message to the base station based on the grant for the first set of
uplink resources, transmit the RRC connection request message to
the base station using one or more of the first set of uplink
resources or the second set of uplink resources, and establish a
connection with the base station based on the RRC connection
request message. The communications manager 915 may be an example
of aspects of the communications manager 1210 described herein.
The communications manager 915, or its sub-components, may be
implemented in hardware, code (e.g., software or firmware) executed
by a processor, or any combination thereof. If implemented in code
executed by a processor, the functions of the communications
manager 915, or its sub-components may be executed by a
general-purpose processor, a digital signal processor (DSP), an
application-specific integrated circuit (ASIC), a field
programmable gate array (FPGA) or other programmable logic device,
discrete gate or transistor logic, discrete hardware components, or
any combination thereof designed to perform the functions described
in the present disclosure.
The communications manager 915, or its sub-components, may be
physically located at various positions, including being
distributed such that portions of functions are implemented at
different physical locations by one or more physical components. In
some examples, the communications manager 915, or its
sub-components, may be a separate and distinct component in
accordance with aspects of the present disclosure. In some
examples, the communications manager 915, or its sub-components,
may be combined with one or more other hardware components,
including but not limited to an input/output (I/O) component, a
transceiver, a network server, another computing device, one or
more other components described in the present disclosure, or a
combination thereof in accordance with aspects of the present
disclosure.
The transmitter 920 may transmit signals generated by other
components of the device 905. In some examples, the transmitter 920
may be collocated with a receiver 910 in a transceiver module. For
example, the transmitter 920 may be an example of aspects of the
transceiver 1220 described with reference to FIG. 12. The
transmitter 920 may utilize a single antenna or a set of
antennas.
FIG. 10 shows a block diagram 1000 of a device 1005 that supports
techniques for using multiple sets of uplink resources in a random
access procedure in accordance with aspects of the present
disclosure. The device 1005 may be an example of aspects of a
device 905, or a UE 115 as described herein. The device 1005 may
include a receiver 1010, a communications manager 1015, and a
transmitter 1040. The device 1005 may also include a processor.
Each of these components may be in communication with one another
(e.g., via one or more buses).
The receiver 1010 may receive information such as packets, user
data, or control information associated with various information
channels (e.g., control channels, data channels, and information
related to techniques for using multiple sets of uplink resources
in a random access procedure, etc.). Information may be passed on
to other components of the device 1005. The receiver 1010 may be an
example of aspects of the transceiver 1220 described with reference
to FIG. 12. The receiver 1010 may utilize a single antenna or a set
of antennas.
The communications manager 1015 may be an example of aspects of the
communications manager 915 as described herein. The communications
manager 1015 may include a random access request message module
1020, a random access response message module 1025, an RRC
connection request message module 1030, and a connection module
1035. The communications manager 1015 may be an example of aspects
of the communications manager 1210 described herein.
The random access request message module 1020 may transmit a random
access request message to a base station.
The random access response message module 1025 may receive a random
access response message from the base station in response to the
random access request message, the random access response message
including a grant for a first set of uplink resources for
transmitting an RRC connection request message to the base
station.
The RRC connection request message module 1030 may determine at
least a second set of uplink resources for transmitting the RRC
connection request message to the base station based on the grant
for the first set of uplink resources and transmit the RRC
connection request message to the base station using one or more of
the first set of uplink resources or the second set of uplink
resources.
The connection module 1035 may establish a connection with the base
station based on the RRC connection request message.
In some implementations, the actions performed by the random access
request message module 1020, the random access response message
module 1025, the RRC connection request message module 1030, and
the connection module 1035, as described herein, may facilitate the
processor 1240, as described with reference to FIG. 12, to more
efficiently cause the device 1005 to perform various functions. For
example, the device 1005 may scale and/or time-shift the RRC
connection request message based on the resources indicated in
uplink grants included in random access response messages received
from the base station. This may provide, for example, a relatively
increased time diversity at the device 1005 for performing LBT
operations (i.e., increased diversity between the different sets of
resources for which the device 1005 may perform LBT operations).
The increased time diversity may, in some cases, correspondingly
increase the probability that the device 1005 successfully performs
LBT procedures according to the uplink grants. Accordingly, the
device 1005 may reduce a number of processing operations at the
processor and other components of the device 1005, which may in
turn provide power savings and conserve processing resources for
the processor of the device 1005.
The transmitter 1040 may transmit signals generated by other
components of the device 1005. In some examples, the transmitter
1040 may be collocated with a receiver 1010 in a transceiver
module. For example, the transmitter 1040 may be an example of
aspects of the transceiver 1220 described with reference to FIG.
12. The transmitter 1040 may utilize a single antenna or a set of
antennas.
FIG. 11 shows a block diagram 1100 of a communications manager 1105
that supports techniques for using multiple sets of uplink
resources in a random access procedure in accordance with aspects
of the present disclosure. The communications manager 1105 may be
an example of aspects of a communications manager 915, a
communications manager 1015, or a communications manager 1210
described herein. The communications manager 1105 may include a
random access request message module 1110, a random access response
message module 1115, an RRC connection request message module 1120,
a connection module 1125, a multiple grant configuration module
1130, a timing information module 1135, a channel access procedure
module 1140, and a signal strength module 1145. Each of these
modules may communicate, directly or indirectly, with one another
(e.g., via one or more buses).
The random access request message module 1110 may transmit a random
access request message to a base station.
The random access response message module 1115 may receive a random
access response message from the base station in response to the
random access request message, the random access response message
including a grant for a first set of uplink resources for
transmitting an RRC connection request message to the base station.
In some cases, the random access response message includes grant
multiplicity information, the grant multiplicity information
indicating a number of grants to be used for repeating transmission
of the RRC connection request message, and where repeating
transmission of the RRC connection request message to the base
station is based on the grant multiplicity information. In some
cases, the random access response message includes one or more
additional grants for at least the second set of uplink resources,
and determining at least the second set of uplink resources is
based on the one or more additional grants.
In some cases, each of the grant and the one or more additional
grants includes a random access preamble identifier for
transmitting the RRC connection request message, each of the random
access preamble identifiers of each of the grant and the one or
more additional grants having a same value. In some cases, each of
the grant and the one or more additional grants includes a random
access preamble identifier for transmitting the RRC connection
request message, one or more of the random access preamble
identifiers of the grant and the one or more additional grants
having different values.
In some cases, each of the grant and the one or more additional
grants includes a temporary cell identifier for transmitting the
RRC connection request message, each of the temporary cell
identifiers of each of the grant and the one or more additional
grants having a same value. In some cases, each of the grant and
the one or more additional grants includes a temporary cell
identifier for transmitting the RRC connection request message, one
or more of the temporary cell identifiers of the grant and the one
or more additional grants having different values.
In some cases, the random access response message indicates beam
information associated with the grant for the first set of uplink
resources, and beam parameters for an uplink beam to be used to
transmit the RRC connection request message are based on the beam
information. In some cases, the beam information indicates a
mapping of one or more beam indexes according to one or more
corresponding random access preamble identifiers.
The RRC connection request message module 1120 may determine at
least a second set of uplink resources for transmitting the RRC
connection request message to the base station based on the grant
for the first set of uplink resources. In some examples, the RRC
connection request message module 1120 may transmit the RRC
connection request message to the base station using one or more of
the first set of uplink resources or the second set of uplink
resources. In some examples, the RRC connection request message
module 1120 may repeat transmission of the RRC connection request
message to the base station using one or more of the first set of
uplink resources or the second set of uplink resources. In some
examples, the RRC connection request message module 1120 may
transmit the RRC connection request message according to the timing
information.
In some examples, the RRC connection request message module 1120
may transmit the RRC connection request message using whichever of
the first set of uplink resources or the second set of uplink
resources has an earliest time component. In some examples, the RRC
connection request message module 1120 may transmit the RRC
connection request message using whichever of the first set of
uplink resources or the second set of uplink resources corresponds
to a first successful channel access procedure. In some examples,
the RRC connection request message module 1120 may transmit the RRC
connection request message using whichever of the first set of
uplink resources or the second set of uplink resources is
associated with a greatest signal strength.
In some examples, the RRC connection request message module 1120
may determine the uplink beam to be used to transmit the RRC
connection request message to the base station based on the beam
parameters for the uplink beam. In some examples, the RRC
connection request message module 1120 may transmit the RRC
connection request message to the base station using the uplink
beam. In some cases, the beam information indicates one or more
downlink beam parameters for a downlink beam used to receive
synchronization signals from the base station, and determining the
uplink beam to be used to transmit the RRC connection request
message is based on a correspondence between the downlink beam
parameters and the uplink beam parameters for the uplink beam. In
some cases, the downlink beam used to receive the synchronization
signals from the base station is different than a second downlink
beam used to receive the random access response message from the
base station.
The connection module 1125 may establish a connection with the base
station based on the RRC connection request message.
The multiple grant configuration module 1130 may receive a multiple
grant configuration in a SIB message, an RMSI message, a dedicated
signaling message, or a combination thereof. In some examples, the
multiple grant configuration module 1130 may determine at least the
second set of uplink resources for transmitting the RRC connection
request message to the base station based on the multiple grant
configuration. In some cases, the multiple grant configuration
indicates a maximum number of grants, a relationship between the
first set of uplink resources and the second set of uplink
resources, an MCS, or a combination thereof.
The timing information module 1135 may receive timing information
from the base station, the timing information indicating a
time-domain offset between the random access response message, the
one or more of the first set of uplink resources, the second set of
uplink resources, or a combination thereof.
The channel access procedure module 1140 may perform a channel
access procedure for both the first set of uplink resources and the
second set of uplink resources. In some cases, each of the grant
and the one or more additional grants includes respective channel
access procedure parameters for the first set of uplink resources
or the second set of uplink resources, and transmitting the RRC
connection request message to the base station is based on a
successful result of one or more of the channel access procedures
according to the respective channel access procedure parameters. In
some cases, the channel access procedure parameters include a
channel access priority, COT information, or a combination thereof,
associated with the corresponding first set of uplink resources or
second set of uplink resources.
The signal strength module 1145 may determine a signal strength
associated with each of the first set of uplink resources and the
second set of uplink resources.
FIG. 12 shows a diagram of a system 1200 including a device 1205
that supports techniques for using multiple sets of uplink
resources in a random access procedure in accordance with aspects
of the present disclosure. The device 1205 may be an example of or
include the components of device 905, device 1005, or a UE 115 as
described herein. The device 1205 may include components for
bi-directional voice and data communications including components
for transmitting and receiving communications, including a
communications manager 1210, an I/O controller 1215, a transceiver
1220, an antenna 1225, memory 1230, and a processor 1240. These
components may be in electronic communication via one or more buses
(e.g., bus 1245).
The communications manager 1210 may transmit a random access
request message to a base station, receive a random access response
message from the base station in response to the random access
request message, the random access response message including a
grant for a first set of uplink resources for transmitting an RRC
connection request message to the base station, determine at least
a second set of uplink resources for transmitting the RRC
connection request message to the base station based on the grant
for the first set of uplink resources, transmit the RRC connection
request message to the base station using one or more of the first
set of uplink resources or the second set of uplink resources, and
establish a connection with the base station based on the RRC
connection request message.
The I/O controller 1215 may manage input and output signals for the
device 1205. The I/O controller 1215 may also manage peripherals
not integrated into the device 1205. In some cases, the I/O
controller 1215 may represent a physical connection or port to an
external peripheral. In some cases, the I/O controller 1215 may
utilize an operating system such as iOS.RTM., ANDROID.RTM.,
MS-DOS.RTM., MS-WINDOWS.RTM., OS/2.RTM., UNIX.RTM., LINUX.RTM., or
another known operating system. In other cases, the I/O controller
1215 may represent or interact with a modem, a keyboard, a mouse, a
touchscreen, or a similar device. In some cases, the I/O controller
1215 may be implemented as part of a processor. In some cases, a
user may interact with the device 1205 via the I/O controller 1215
or via hardware components controlled by the I/O controller
1215.
The transceiver 1220 may communicate bi-directionally, via one or
more antennas, wired, or wireless links as described above. For
example, the transceiver 1220 may represent a wireless transceiver
and may communicate bi-directionally with another wireless
transceiver. The transceiver 1220 may also include a modem to
modulate the packets and provide the modulated packets to the
antennas for transmission, and to demodulate packets received from
the antennas.
In some cases, the wireless device may include a single antenna
1225. However, in some cases the device may have more than one
antenna 1225, which may be capable of concurrently transmitting or
receiving multiple wireless transmissions.
The memory 1230 may include random-access memory (RAM) and
read-only memory (ROM). The memory 1230 may store
computer-readable, computer-executable code 1235 including
instructions that, when executed, cause the processor to perform
various functions described herein. In some cases, the memory 1230
may contain, among other things, a basic input/output system (BIOS)
which may control basic hardware or software operation such as the
interaction with peripheral components or devices.
The processor 1240 may include an intelligent hardware device,
(e.g., a general-purpose processor, a DSP, a CPU, a
microcontroller, an ASIC, an FPGA, a programmable logic device, a
discrete gate or transistor logic component, a discrete hardware
component, or any combination thereof). In some cases, the
processor 1240 may be configured to operate a memory array using a
memory controller. In other cases, a memory controller may be
integrated into the processor 1240. The processor 1240 may be
configured to execute computer-readable instructions stored in a
memory (e.g., the memory 1230) to cause the device 1205 to perform
various functions (e.g., functions or tasks supporting techniques
for using multiple sets of uplink resources in a random access
procedure).
The code 1235 may include instructions to implement aspects of the
present disclosure, including instructions to support wireless
communications. The code 1235 may be stored in a non-transitory
computer-readable medium such as system memory or other type of
memory. In some cases, the code 1235 may not be directly executable
by the processor 1240 but may cause a computer (e.g., when compiled
and executed) to perform functions described herein.
FIG. 13 shows a block diagram 1300 of a device 1305 that supports
techniques for using multiple sets of uplink resources in a random
access procedure in accordance with aspects of the present
disclosure. The device 1305 may be an example of aspects of a base
station 105 as described herein. The device 1305 may include a
receiver 1310, a communications manager 1315, and a transmitter
1320. The device 1305 may also include a processor. Each of these
components may be in communication with one another (e.g., via one
or more buses).
The receiver 1310 may receive information such as packets, user
data, or control information associated with various information
channels (e.g., control channels, data channels, and information
related to techniques for using multiple sets of uplink resources
in a random access procedure, etc.). Information may be passed on
to other components of the device 1305. The receiver 1310 may be an
example of aspects of the transceiver 1620 described with reference
to FIG. 16. The receiver 1310 may utilize a single antenna or a set
of antennas.
The communications manager 1315 may receive a random access request
message from a UE, transmit a random access response message to the
UE in response to the random access request message, the random
access response message including a grant for a first set of uplink
resources for receiving an RRC connection request message from the
UE, receive the RRC connection request message from the UE using
one or more of the first set of uplink resources or a second set of
uplink resources, the second set of uplink resources based on the
grant for the first set of uplink resources, and establish a
connection with the UE based on the RRC connection request message.
The communications manager 1315 may be an example of aspects of the
communications manager 1610 described herein.
The communications manager 1315, or its sub-components, may be
implemented in hardware, code (e.g., software or firmware) executed
by a processor, or any combination thereof. If implemented in code
executed by a processor, the functions of the communications
manager 1315, or its sub-components may be executed by a
general-purpose processor, a DSP, an ASIC, a FPGA or other
programmable logic device, discrete gate or transistor logic,
discrete hardware components, or any combination thereof designed
to perform the functions described in the present disclosure.
The communications manager 1315, or its sub-components, may be
physically located at various positions, including being
distributed such that portions of functions are implemented at
different physical locations by one or more physical components. In
some examples, the communications manager 1315, or its
sub-components, may be a separate and distinct component in
accordance with aspects of the present disclosure. In some
examples, the communications manager 1315, or its sub-components,
may be combined with one or more other hardware components,
including but not limited to an input/output (I/O) component, a
transceiver, a network server, another computing device, one or
more other components described in the present disclosure, or a
combination thereof in accordance with aspects of the present
disclosure.
The transmitter 1320 may transmit signals generated by other
components of the device 1305. In some examples, the transmitter
1320 may be collocated with a receiver 1310 in a transceiver
module. For example, the transmitter 1320 may be an example of
aspects of the transceiver 1620 described with reference to FIG.
16. The transmitter 1320 may utilize a single antenna or a set of
antennas.
FIG. 14 shows a block diagram 1400 of a device 1405 that supports
techniques for using multiple sets of uplink resources in a random
access procedure in accordance with aspects of the present
disclosure. The device 1405 may be an example of aspects of a
device 1305, or a base station 105 as described herein. The device
1405 may include a receiver 1410, a communications manager 1415,
and a transmitter 1440. The device 1405 may also include a
processor. Each of these components may be in communication with
one another (e.g., via one or more buses).
The receiver 1410 may receive information such as packets, user
data, or control information associated with various information
channels (e.g., control channels, data channels, and information
related to techniques for using multiple sets of uplink resources
in a random access procedure, etc.). Information may be passed on
to other components of the device 1405. The receiver 1410 may be an
example of aspects of the transceiver 1620 described with reference
to FIG. 16. The receiver 1410 may utilize a single antenna or a set
of antennas.
The communications manager 1415 may be an example of aspects of the
communications manager 1315 as described herein. The communications
manager 1415 may include a random access request message manager
1420, a random access response message manager 1425, an RRC
connection request message manager 1430, and a connection manager
1435. The communications manager 1415 may be an example of aspects
of the communications manager 1610 described herein.
The random access request message manager 1420 may receive a random
access request message from a UE.
The random access response message manager 1425 may transmit a
random access response message to the UE in response to the random
access request message, the random access response message
including a grant for a first set of uplink resources for receiving
an RRC connection request message from the UE.
The RRC connection request message manager 1430 may receive the RRC
connection request message from the UE using one or more of the
first set of uplink resources or a second set of uplink resources,
the second set of uplink resources based on the grant for the first
set of uplink resources.
The connection manager 1435 may establish a connection with the UE
based on the RRC connection request message.
In some implementations, the actions performed by the random access
request message manager 1420, the random access response message
manager 1425, the RRC connection request message manager 1430, and
the connection manager 1435, as described herein, may facilitate
the processor 1640, as described with reference to FIG. 16, to more
efficiently cause the device 1405 to perform various functions. For
example, the device 1405 indicating resources in uplink grants
included in random access response messages transmitted to the UE
may facilitate the UE to scale and/or time-shift the RRC connection
request message, which may relatively increase time diversity for
the UE to perform LBT operations (i.e., providing increased
diversity between different sets of resources for which the UE may
perform LBT operations). The increased time diversity may, in some
cases, correspondingly increase the probability that the UE
successfully performs LBT procedures according to the uplink
grants. This may conserve over-the-air resources for communications
between the device 1405 and, for example, other UEs, as well as
providing efficiencies at the device 14-05. The device 1405 may
reduce a number of processing operations at the processor and other
components of the device 1405, which may in turn provide power
savings and conserve processing resources for the processor of the
device 1405.
The transmitter 1440 may transmit signals generated by other
components of the device 1405. In some examples, the transmitter
1440 may be collocated with a receiver 1410 in a transceiver
module. For example, the transmitter 1440 may be an example of
aspects of the transceiver 1620 described with reference to FIG.
16. The transmitter 1440 may utilize a single antenna or a set of
antennas.
FIG. 15 shows a block diagram 1500 of a communications manager 1505
that supports techniques for using multiple sets of uplink
resources in a random access procedure in accordance with aspects
of the present disclosure. The communications manager 1505 may be
an example of aspects of a communications manager 1315, a
communications manager 1415, or a communications manager 1610
described herein. The communications manager 1505 may include a
random access request message manager 1510, a random access
response message manager 1515, an RRC connection request message
manager 1520, a connection manager 1525, and a timing information
manager 1530. Each of these modules may communicate, directly or
indirectly, with one another (e.g., via one or more buses).
The random access request message manager 1510 may receive a random
access request message from a UE.
The random access response message manager 1515 may transmit a
random access response message to the UE in response to the random
access request message, the random access response message
including a grant for a first set of uplink resources for receiving
an RRC connection request message from the UE.
In some cases, the random access response message includes one or
more additional grants for the first set of uplink resources, and
the second set of uplink resources are based on the one or more
additional grants for the first set of uplink resources. In some
cases, each of the grant and the one or more additional grants
includes a random access preamble identifier for transmitting the
RRC connection request message, each of the random access preamble
identifiers of each of the grant and the one or more additional
grants having a same value. In some cases, each of the grant and
the one or more additional grants includes a random access preamble
identifier for transmitting the RRC connection request message, one
or more of the random access preamble identifiers of the grant and
the one or more additional grants having different values.
In some cases, each of the grant and the one or more additional
grants includes a temporary cell identifier for transmitting the
RRC connection request message, each of the temporary cell
identifiers of each of the grant and the one or more additional
grants having a same value. In some cases, each of the grant and
the one or more additional grants includes a temporary cell
identifier for transmitting the RRC connection request message, one
or more of the temporary cell identifiers of the grant and the one
or more additional grants having different values.
In some examples, the random access response message manager 1515
may identify beam information associated with the grant for the
first set of uplink resources, where the random access response
message indicates the beam information, and beam parameters for an
uplink beam used to receive the RRC connection request message are
based on the beam information. In some cases, the beam information
indicates a mapping of one or more beam indexes according to one or
more corresponding random access preamble identifiers. In some
cases, the beam information indicates one or more downlink beam
parameters for a downlink beam used to transmit synchronization
signals to the UE, and the uplink beam used to receive the RRC
connection request message is based on a correspondence between the
downlink beam parameters and the uplink beam parameters for the
uplink beam. In some cases, the downlink beam used to transmit the
synchronization signals to the UE is different than a second
downlink beam used to transmit the random access response message
to the UE.
The RRC connection request message manager 1520 may receive the RRC
connection request message from the UE using one or more of the
first set of uplink resources or a second set of uplink resources,
the second set of uplink resources based on the grant for the first
set of uplink resources. In some examples, the RRC connection
request message manager 1520 may receive a repeated transmission of
the RRC connection request message from the UE using one or more of
the first set of uplink resources or the second set of uplink
resources.
In some examples, the RRC connection request message manager 1520
may receive the RRC connection request message according to the
timing information.
In some examples, the RRC connection request message manager 1520
may receive the RRC connection request message using whichever of
the first set of uplink resources or the second set of uplink
resources has an earliest time component. In some examples, the RRC
connection request message manager 1520 may receive the RRC
connection request message using whichever of the first set of
uplink resources or the second set of uplink resources corresponds
to a first successful channel access procedure. In some examples,
the RRC connection request message manager 1520 may receive the RRC
connection request message using whichever of the first set of
uplink resources or the second set of uplink resources is
associated with a greatest signal strength.
In some examples, the RRC connection request message manager 1520
may receive the RRC connection request message from the UE using
the uplink beam according to the beam parameters.
In some cases, the repeated transmission of the RRC connection
request message to the base station is based on grant multiplicity
information included in the random access response message.
In some cases, each of the grant and the one or more additional
grants includes respective channel access procedure parameters for
the first set of uplink resources or the second set of uplink
resources, and receiving the RRC connection request message from
the UE is based on a successful result of one or more of the
channel access procedures according to the respective channel
access procedure parameters. In some cases, the channel access
procedure parameters include a channel access priority, COT
information, or a combination thereof, associated with the
corresponding first set of uplink resources or second set of uplink
resources.
The connection manager 1525 may establish a connection with the UE
based on the RRC connection request message.
The timing information manager 1530 may transmit timing information
to the UE, the timing information indicating a time-domain offset
between the random access response message, the one or more of the
first set of uplink resources, the second set of uplink resources,
or a combination thereof.
FIG. 16 shows a diagram of a system 1600 including a device 1605
that supports techniques for using multiple sets of uplink
resources in a random access procedure in accordance with aspects
of the present disclosure. The device 1605 may be an example of or
include the components of device 1305, device 1405, or a base
station 105 as described herein. The device 1605 may include
components for bi-directional voice and data communications
including components for transmitting and receiving communications,
including a communications manager 1610, a network communications
manager 1615, a transceiver 1620, an antenna 1625, memory 1630, a
processor 1640, and an inter-station communications manager 1645.
These components may be in electronic communication via one or more
buses (e.g., bus 1650).
The communications manager 1610 may receive a random access request
message from a UE, transmit a random access response message to the
UE in response to the random access request message, the random
access response message including a grant for a first set of uplink
resources for receiving an RRC connection request message from the
UE, receive the RRC connection request message from the UE using
one or more of the first set of uplink resources or a second set of
uplink resources, the second set of uplink resources based on the
grant for the first set of uplink resources, and establish a
connection with the UE based on the RRC connection request
message.
The network communications manager 1615 may manage communications
with the core network (e.g., via one or more wired backhaul links).
For example, the network communications manager 1615 may manage the
transfer of data communications for client devices, such as one or
more UEs 115.
The transceiver 1620 may communicate bi-directionally, via one or
more antennas, wired, or wireless links as described above. For
example, the transceiver 1620 may represent a wireless transceiver
and may communicate bi-directionally with another wireless
transceiver. The transceiver 1620 may also include a modem to
modulate the packets and provide the modulated packets to the
antennas for transmission, and to demodulate packets received from
the antennas.
In some cases, the wireless device may include a single antenna
1625. However, in some cases the device may have more than one
antenna 1625, which may be capable of concurrently transmitting or
receiving multiple wireless transmissions.
The memory 1630 may include RAM, ROM, or a combination thereof. The
memory 1630 may store computer-readable code 1635 including
instructions that, when executed by a processor (e.g., the
processor 1640) cause the device to perform various functions
described herein. In some cases, the memory 1630 may contain, among
other things, a BIOS which may control basic hardware or software
operation such as the interaction with peripheral components or
devices.
The processor 1640 may include an intelligent hardware device,
(e.g., a general-purpose processor, a DSP, a CPU, a
microcontroller, an ASIC, an FPGA, a programmable logic device, a
discrete gate or transistor logic component, a discrete hardware
component, or any combination thereof). In some cases, the
processor 1640 may be configured to operate a memory array using a
memory controller. In some cases, a memory controller may be
integrated into processor 1640. The processor 1640 may be
configured to execute computer-readable instructions stored in a
memory (e.g., the memory 1630) to cause the device 1605 to perform
various functions (e.g., functions or tasks supporting techniques
for using multiple sets of uplink resources in a random access
procedure).
The inter-station communications manager 1645 may manage
communications with other base station 105, and may include a
controller or scheduler for controlling communications with UEs 115
in cooperation with other base stations 105. For example, the
inter-station communications manager 1645 may coordinate scheduling
for transmissions to UEs 115 for various interference mitigation
techniques such as beamforming or joint transmission. In some
examples, the inter-station communications manager 1645 may provide
an X2 interface within an LTE/LTE-A wireless communications network
technology to provide communication between base stations 105.
The code 1635 may include instructions to implement aspects of the
present disclosure, including instructions to support wireless
communications. The code 1635 may be stored in a non-transitory
computer-readable medium such as system memory or other type of
memory. In some cases, the code 1635 may not be directly executable
by the processor 1640 but may cause a computer (e.g., when compiled
and executed) to perform functions described herein.
FIG. 17 shows a flowchart illustrating a method 1700 that supports
techniques for using multiple sets of uplink resources in a random
access procedure in accordance with aspects of the present
disclosure. The operations of method 1700 may be implemented by a
UE 115 or its components as described herein. For example, the
operations of method 1700 may be performed by a communications
manager as described with reference to FIGS. 9 through 12. In some
examples, a UE may execute a set of instructions to control the
functional elements of the UE to perform the functions described
below. Additionally or alternatively, a UE may perform aspects of
the functions described below using special-purpose hardware.
At 1705, the UE may transmit a random access request message to a
base station. The operations of 1705 may be performed according to
the methods described herein. In some examples, aspects of the
operations of 1705 may be performed by a random access request
message module as described with reference to FIGS. 9 through
12.
At 1710, the UE may receive a random access response message from
the base station in response to the random access request message,
the random access response message including a grant for a first
set of uplink resources for transmitting an RRC connection request
message to the base station. The operations of 1710 may be
performed according to the methods described herein. In some
examples, aspects of the operations of 1710 may be performed by a
random access response message module as described with reference
to FIGS. 9 through 12.
At 1715, the UE may determine at least a second set of uplink
resources for transmitting the RRC connection request message to
the base station based on the grant for the first set of uplink
resources. The operations of 1715 may be performed according to the
methods described herein. In some examples, aspects of the
operations of 1715 may be performed by an RRC connection request
message module as described with reference to FIGS. 9 through
12.
At 1720, the UE may transmit the RRC connection request message to
the base station using one or more of the first set of uplink
resources or the second set of uplink resources. The operations of
1720 may be performed according to the methods described herein. In
some examples, aspects of the operations of 1720 may be performed
by an RRC connection request message module as described with
reference to FIGS. 9 through 12.
At 1725, the UE may establish a connection with the base station
based on the RRC connection request message. The operations of 1725
may be performed according to the methods described herein. In some
examples, aspects of the operations of 1725 may be performed by a
connection module as described with reference to FIGS. 9 through
12.
FIG. 18 shows a flowchart illustrating a method 1800 that supports
techniques for using multiple sets of uplink resources in a random
access procedure in accordance with aspects of the present
disclosure. The operations of method 1800 may be implemented by a
UE 115 or its components as described herein. For example, the
operations of method 1800 may be performed by a communications
manager as described with reference to FIGS. 9 through 12. In some
examples, a UE may execute a set of instructions to control the
functional elements of the UE to perform the functions described
below. Additionally or alternatively, a UE may perform aspects of
the functions described below using special-purpose hardware.
At 1805, the UE may transmit a random access request message to a
base station. The operations of 1805 may be performed according to
the methods described herein. In some examples, aspects of the
operations of 1805 may be performed by a random access request
message module as described with reference to FIGS. 9 through
12.
At 1810, the UE may receive a random access response message from
the base station in response to the random access request message,
the random access response message including a grant for a first
set of uplink resources for transmitting an RRC connection request
message to the base station. The operations of 1810 may be
performed according to the methods described herein. In some
examples, aspects of the operations of 1810 may be performed by a
random access response message module as described with reference
to FIGS. 9 through 12.
At 1815, the UE may determine at least a second set of uplink
resources for transmitting the RRC connection request message to
the base station based on the grant for the first set of uplink
resources. The operations of 1815 may be performed according to the
methods described herein. In some examples, aspects of the
operations of 1815 may be performed by an RRC connection request
message module as described with reference to FIGS. 9 through
12.
At 1820, the UE may receive a multiple grant configuration in a SIB
message, an RMSI, a dedicated signaling message, or a combination
thereof. The operations of 1820 may be performed according to the
methods described herein. In some examples, aspects of the
operations of 1820 may be performed by a multiple grant
configuration module as described with reference to FIGS. 9 through
12.
At 1825, the UE may transmit the RRC connection request message to
the base station using one or more of the first set of uplink
resources or the second set of uplink resources. The operations of
1825 may be performed according to the methods described herein. In
some examples, aspects of the operations of 1825 may be performed
by an RRC connection request message module as described with
reference to FIGS. 9 through 12.
At 1830, the UE may establish a connection with the base station
based on the RRC connection request message. The operations of 1830
may be performed according to the methods described herein. In some
examples, aspects of the operations of 1830 may be performed by a
connection module as described with reference to FIGS. 9 through
12.
FIG. 19 shows a flowchart illustrating a method 1900 that supports
techniques for using multiple sets of uplink resources in a random
access procedure in accordance with aspects of the present
disclosure. The operations of method 1900 may be implemented by a
UE 115 or its components as described herein. For example, the
operations of method 1900 may be performed by a communications
manager as described with reference to FIGS. 9 through 12. In some
examples, a UE may execute a set of instructions to control the
functional elements of the UE to perform the functions described
below. Additionally or alternatively, a UE may perform aspects of
the functions described below using special-purpose hardware.
At 1905, the UE may transmit a random access request message to a
base station. The operations of 1905 may be performed according to
the methods described herein. In some examples, aspects of the
operations of 1905 may be performed by a random access request
message module as described with reference to FIGS. 9 through
12.
At 1910, the UE may receive a random access response message from
the base station in response to the random access request message,
the random access response message including a grant for a first
set of uplink resources for transmitting an RRC connection request
message to the base station. The operations of 1910 may be
performed according to the methods described herein. In some
examples, aspects of the operations of 1910 may be performed by a
random access response message module as described with reference
to FIGS. 9 through 12.
At 1915, the UE may determine at least a second set of uplink
resources for transmitting the RRC connection request message to
the base station based on the grant for the first set of uplink
resources. The operations of 1915 may be performed according to the
methods described herein. In some examples, aspects of the
operations of 1915 may be performed by an RRC connection request
message module as described with reference to FIGS. 9 through
12.
At 1920, the UE may receive a multiple grant configuration in a SIB
message, an RMSI, a dedicated signaling message, or a combination
thereof. The operations of 1920 may be performed according to the
methods described herein. In some examples, aspects of the
operations of 1920 may be performed by a multiple grant
configuration module as described with reference to FIGS. 9 through
12.
At 1925, the UE may determine at least the second set of uplink
resources for transmitting the RRC connection request message to
the base station based on the multiple grant configuration. The
operations of 1925 may be performed according to the methods
described herein. In some examples, aspects of the operations of
1925 may be performed by a multiple grant configuration module as
described with reference to FIGS. 9 through 12.
At 1930, the UE may transmit the RRC connection request message to
the base station using one or more of the first set of uplink
resources or the second set of uplink resources. The operations of
1930 may be performed according to the methods described herein. In
some examples, aspects of the operations of 1930 may be performed
by an RRC connection request message module as described with
reference to FIGS. 9 through 12.
At 1935, the UE may establish a connection with the base station
based on the RRC connection request message. The operations of 1935
may be performed according to the methods described herein. In some
examples, aspects of the operations of 1935 may be performed by a
connection module as described with reference to FIGS. 9 through
12.
FIG. 20 shows a flowchart illustrating a method 2000 that supports
techniques for using multiple sets of uplink resources in a random
access procedure in accordance with aspects of the present
disclosure. The operations of method 2000 may be implemented by a
UE 115 or its components as described herein. For example, the
operations of method 2000 may be performed by a communications
manager as described with reference to FIGS. 9 through 12. In some
examples, a UE may execute a set of instructions to control the
functional elements of the UE to perform the functions described
below. Additionally or alternatively, a UE may perform aspects of
the functions described below using special-purpose hardware.
At 2005, the UE may transmit a random access request message to a
base station. The operations of 2005 may be performed according to
the methods described herein. In some examples, aspects of the
operations of 2005 may be performed by a random access request
message module as described with reference to FIGS. 9 through
12.
At 2010, the UE may receive a random access response message from
the base station in response to the random access request message,
the random access response message including a grant for a first
set of uplink resources for transmitting an RRC connection request
message to the base station. The operations of 2010 may be
performed according to the methods described herein. In some
examples, aspects of the operations of 2010 may be performed by a
random access response message module as described with reference
to FIGS. 9 through 12.
At 2015, the UE may determine at least a second set of uplink
resources for transmitting the RRC connection request message to
the base station based on the grant for the first set of uplink
resources. The operations of 2015 may be performed according to the
methods described herein. In some examples, aspects of the
operations of 2015 may be performed by an RRC connection request
message module as described with reference to FIGS. 9 through
12.
At 2020, the UE may transmit the RRC connection request message to
the base station using one or more of the first set of uplink
resources or the second set of uplink resources. The operations of
2020 may be performed according to the methods described herein. In
some examples, aspects of the operations of 2020 may be performed
by an RRC connection request message module as described with
reference to FIGS. 9 through 12.
At 2025, the UE may repeat transmission of the RRC connection
request message to the base station using one or more of the first
set of uplink resources or the second set of uplink resources. The
operations of 2025 may be performed according to the methods
described herein. In some examples, aspects of the operations of
2025 may be performed by an RRC connection request message module
as described with reference to FIGS. 9 through 12.
At 2030, the UE may establish a connection with the base station
based on the RRC connection request message. The operations of 2030
may be performed according to the methods described herein. In some
examples, aspects of the operations of 2030 may be performed by a
connection module as described with reference to FIGS. 9 through
12.
FIG. 21 shows a flowchart illustrating a method 2100 that supports
techniques for using multiple sets of uplink resources in a random
access procedure in accordance with aspects of the present
disclosure. The operations of method 2100 may be implemented by a
UE 115 or its components as described herein. For example, the
operations of method 2100 may be performed by a communications
manager as described with reference to FIGS. 9 through 12. In some
examples, a UE may execute a set of instructions to control the
functional elements of the UE to perform the functions described
below. Additionally or alternatively, a UE may perform aspects of
the functions described below using special-purpose hardware.
At 2105, the UE may transmit a random access request message to a
base station. The operations of 2105 may be performed according to
the methods described herein. In some examples, aspects of the
operations of 2105 may be performed by a random access request
message module as described with reference to FIGS. 9 through
12.
At 2110, the UE may receive a random access response message from
the base station in response to the random access request message,
the random access response message including a grant for a first
set of uplink resources for transmitting an RRC connection request
message to the base station. The operations of 2110 may be
performed according to the methods described herein. In some
examples, aspects of the operations of 2110 may be performed by a
random access response message module as described with reference
to FIGS. 9 through 12.
At 2115, the UE may determine at least a second set of uplink
resources for transmitting the RRC connection request message to
the base station based on the grant for the first set of uplink
resources. The operations of 2115 may be performed according to the
methods described herein. In some examples, aspects of the
operations of 2115 may be performed by an RRC connection request
message module as described with reference to FIGS. 9 through
12.
At 2120, the UE may perform a channel access procedure for both the
first set of uplink resources and the second set of uplink
resources. The operations of 2120 may be performed according to the
methods described herein. In some examples, aspects of the
operations of 2120 may be performed by a channel access procedure
module as described with reference to FIGS. 9 through 12.
At 2125, the UE may transmit the RRC connection request message
using whichever of the first set of uplink resources or the second
set of uplink resources corresponds to a first successful channel
access procedure. The operations of 2125 may be performed according
to the methods described herein. In some examples, aspects of the
operations of 2125 may be performed by an RRC connection request
message module as described with reference to FIGS. 9 through
12.
At 2130, the UE may establish a connection with the base station
based on the RRC connection request message. The operations of 2130
may be performed according to the methods described herein. In some
examples, aspects of the operations of 2130 may be performed by a
connection module as described with reference to FIGS. 9 through
12.
FIG. 22 shows a flowchart illustrating a method 2200 that supports
techniques for using multiple sets of uplink resources in a random
access procedure in accordance with aspects of the present
disclosure. The operations of method 2200 may be implemented by a
base station 105 or its components as described herein. For
example, the operations of method 2200 may be performed by a
communications manager as described with reference to FIGS. 13
through 16. In some examples, a base station may execute a set of
instructions to control the functional elements of the base station
to perform the functions described below. Additionally or
alternatively, a base station may perform aspects of the functions
described below using special-purpose hardware.
At 2205, the base station may receive a random access request
message from a UE. The operations of 2205 may be performed
according to the methods described herein. In some examples,
aspects of the operations of 2205 may be performed by a random
access request message manager as described with reference to FIGS.
13 through 16.
At 2210, the base station may transmit a random access response
message to the UE in response to the random access request message,
the random access response message including a grant for a first
set of uplink resources for receiving an RRC connection request
message from the UE. The operations of 2210 may be performed
according to the methods described herein. In some examples,
aspects of the operations of 2210 may be performed by a random
access response message manager as described with reference to
FIGS. 13 through 16.
At 2215, the base station may receive the RRC connection request
message from the UE using one or more of the first set of uplink
resources or a second set of uplink resources, the second set of
uplink resources based on the grant for the first set of uplink
resources. The operations of 2215 may be performed according to the
methods described herein. In some examples, aspects of the
operations of 2215 may be performed by an RRC connection request
message manager as described with reference to FIGS. 13 through
16.
At 2220, the base station may establish a connection with the UE
based on the RRC connection request message. The operations of 2220
may be performed according to the methods described herein. In some
examples, aspects of the operations of 2220 may be performed by a
connection manager as described with reference to FIGS. 13 through
16.
FIG. 23 shows a flowchart illustrating a method 2300 that supports
techniques for using multiple sets of uplink resources in a random
access procedure in accordance with aspects of the present
disclosure. The operations of method 2300 may be implemented by a
base station 105 or its components as described herein. For
example, the operations of method 2300 may be performed by a
communications manager as described with reference to FIGS. 13
through 16. In some examples, a base station may execute a set of
instructions to control the functional elements of the base station
to perform the functions described below. Additionally or
alternatively, a base station may perform aspects of the functions
described below using special-purpose hardware.
At 2305, the base station may receive a random access request
message from a UE. The operations of 2305 may be performed
according to the methods described herein. In some examples,
aspects of the operations of 2305 may be performed by a random
access request message manager as described with reference to FIGS.
13 through 16.
At 2310, the base station may transmit a random access response
message to the UE in response to the random access request message,
the random access response message including a grant for a first
set of uplink resources for receiving an RRC connection request
message from the UE. The operations of 2310 may be performed
according to the methods described herein. In some examples,
aspects of the operations of 2310 may be performed by a random
access response message manager as described with reference to
FIGS. 13 through 16.
At 2315, the base station may receive the RRC connection request
message from the UE using one or more of the first set of uplink
resources or a second set of uplink resources, the second set of
uplink resources based on the grant for the first set of uplink
resources. The operations of 2315 may be performed according to the
methods described herein. In some examples, aspects of the
operations of 2315 may be performed by an RRC connection request
message manager as described with reference to FIGS. 13 through
16.
At 2320, the base station may receive a repeated transmission of
the RRC connection request message from the UE using one or more of
the first set of uplink resources or the second set of uplink
resources. The operations of 2320 may be performed according to the
methods described herein. In some examples, aspects of the
operations of 2320 may be performed by an RRC connection request
message manager as described with reference to FIGS. 13 through
16.
At 2325, the base station may establish a connection with the UE
based on the RRC connection request message. The operations of 2325
may be performed according to the methods described herein. In some
examples, aspects of the operations of 2325 may be performed by a
connection manager as described with reference to FIGS. 13 through
16.
It should be noted that the methods described herein describe
possible implementations, and that the operations and the steps may
be rearranged or otherwise modified and that other implementations
are possible. Further, aspects from two or more of the methods may
be combined.
Techniques described herein may be used for various wireless
communications systems such as code division multiple access
(CDMA), time division multiple access (TDMA), frequency division
multiple access (FDMA), orthogonal frequency division multiple
access (OFDMA), single carrier frequency division multiple access
(SC-FDMA), and other systems. A CDMA system may implement a radio
technology such as CDMA2000, Universal Terrestrial Radio Access
(UTRA), etc. CDMA2000 covers IS-2000, IS-95, and IS-856 standards.
IS-2000 Releases may be commonly referred to as CDMA2000 1.times.,
1X, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000
1.times.EV-DO, High Rate Packet Data (HRPD), etc. UTRA includes
Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system may
implement a radio technology such as Global System for Mobile
Communications (GSM).
An OFDMA system may implement a radio technology such as Ultra
Mobile Broadband (UMB), E-UTRA, Institute of Electrical and
Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX),
IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal
Mobile Telecommunications System (UMTS). LTE, LTE-A, and LTE-A Pro
are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE,
LTE-A, LTE-A Pro, NR, and GSM are described in documents from the
organization named "3rd Generation Partnership Project" (3GPP).
CDMA2000 and UMB are described in documents from an organization
named "3rd Generation Partnership Project 2" (3GPP2). The
techniques described herein may be used for the systems and radio
technologies mentioned herein as well as other systems and radio
technologies. While aspects of an LTE, LTE-A, LTE-A Pro, or NR
system may be described for purposes of example, and LTE, LTE-A,
LTE-A Pro, or NR terminology may be used in much of the
description, the techniques described herein are applicable beyond
LTE, LTE-A, LTE-A Pro, or NR applications.
A macro cell generally covers a relatively large geographic area
(e.g., several kilometers in radius) and may allow unrestricted
access by UEs with service subscriptions with the network provider.
A small cell may be associated with a lower-powered base station,
as compared with a macro cell, and a small cell may operate in the
same or different (e.g., licensed, unlicensed, etc.) frequency
bands as macro cells. Small cells may include pico cells, femto
cells, and micro cells according to various examples. A pico cell,
for example, may cover a small geographic area and may allow
unrestricted access by UEs with service subscriptions with the
network provider. A femto cell may also cover a small geographic
area (e.g., a home) and may provide restricted access by UEs having
an association with the femto cell (e.g., UEs in a closed
subscriber group (CSG), UEs for users in the home, and the like).
An eNB for a macro cell may be referred to as a macro eNB. An eNB
for a small cell may be referred to as a small cell eNB, a pico
eNB, a femto eNB, or a home eNB. An eNB may support one or multiple
(e.g., two, three, four, and the like) cells, and may also support
communications using one or multiple component carriers.
The wireless communications systems described herein may support
synchronous or asynchronous operation. For synchronous operation,
the base stations may have similar frame timing, and transmissions
from different base stations may be approximately aligned in time.
For asynchronous operation, the base stations may have different
frame timing, and transmissions from different base stations may
not be aligned in time. The techniques described herein may be used
for either synchronous or asynchronous operations.
Information and signals described herein may be represented using
any of a variety of different technologies and techniques. For
example, data, instructions, commands, information, signals, bits,
symbols, and chips that may be referenced throughout the
description may be represented by voltages, currents,
electromagnetic waves, magnetic fields or particles, optical fields
or particles, or any combination thereof.
The various illustrative blocks and modules described in connection
with the disclosure herein may be implemented or performed with a
general-purpose processor, a DSP, an ASIC, an FPGA, or other
programmable logic device, discrete gate or transistor logic,
discrete hardware components, or any combination thereof designed
to perform the functions described herein. A general-purpose
processor may be a microprocessor, but in the alternative, the
processor may be any conventional processor, controller,
microcontroller, or state machine. A processor may also be
implemented as a combination of computing devices (e.g., a
combination of a DSP and a microprocessor, multiple
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration).
The functions described herein may be implemented in hardware,
software executed by a processor, firmware, or any combination
thereof. If implemented in software executed by a processor, the
functions may be stored on or transmitted over as one or more
instructions or code on a computer-readable medium. Other examples
and implementations are within the scope of the disclosure and
appended claims. For example, due to the nature of software,
functions described herein can be implemented using software
executed by a processor, hardware, firmware, hardwiring, or
combinations of any of these. Features implementing functions may
also be physically located at various positions, including being
distributed such that portions of functions are implemented at
different physical locations.
Computer-readable media includes both non-transitory computer
storage media and communication media including any medium that
facilitates transfer of a computer program from one place to
another. A non-transitory storage medium may be any available
medium that can be accessed by a general purpose or special purpose
computer. By way of example, and not limitation, non-transitory
computer-readable media may include RAM, ROM, electrically erasable
programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or
other optical disk storage, magnetic disk storage or other magnetic
storage devices, or any other non-transitory medium that can be
used to carry or store desired program code means in the form of
instructions or data structures and that can be accessed by a
general-purpose or special-purpose computer, or a general-purpose
or special-purpose processor. Also, any connection is properly
termed a computer-readable medium. For example, if the software is
transmitted from a website, server, or other remote source using a
coaxial cable, fiber optic cable, twisted pair, digital subscriber
line (DSL), or wireless technologies such as infrared, radio, and
microwave, then the coaxial cable, fiber optic cable, twisted pair,
DSL, or wireless technologies such as infrared, radio, and
microwave are included in the definition of medium. Disk and disc,
as used herein, include CD, laser disc, optical disc, digital
versatile disc (DVD), floppy disk and Blu-ray disc where disks
usually reproduce data magnetically, while discs reproduce data
optically with lasers. Combinations of the above are also included
within the scope of computer-readable media.
As used herein, including in the claims, "or" as used in a list of
items (e.g., a list of items prefaced by a phrase such as "at least
one of" or "one or more of") indicates an inclusive list such that,
for example, a list of at least one of A, B, or C means A or B or C
or AB or AC or BC or ABC (i.e., A and B and C). Also, as used
herein, the phrase "based on" shall not be construed as a reference
to a closed set of conditions. For example, an exemplary step that
is described as "based on condition A" may be based on both a
condition A and a condition B without departing from the scope of
the present disclosure. In other words, as used herein, the phrase
"based on" shall be construed in the same manner as the phrase
"based at least in part on."
In the appended figures, similar components or features may have
the same reference label. Further, various components of the same
type may be distinguished by following the reference label by a
dash and a second label that distinguishes among the similar
components. If just the first reference label is used in the
specification, the description is applicable to any one of the
similar components having the same first reference label
irrespective of the second reference label, or other subsequent
reference label.
The description set forth herein, in connection with the appended
drawings, describes example configurations and does not represent
all the examples that may be implemented or that are within the
scope of the claims. The term "exemplary" used herein means
"serving as an example, instance, or illustration," and not
"preferred" or "advantageous over other examples." The detailed
description includes specific details for the purpose of providing
an understanding of the described techniques. These techniques,
however, may be practiced without these specific details. In some
instances, well-known structures and devices are shown in block
diagram form in order to avoid obscuring the concepts of the
described examples.
The description herein is provided to enable a person skilled in
the art to make or use the disclosure. Various modifications to the
disclosure will be readily apparent to those skilled in the art,
and the generic principles defined herein may be applied to other
variations without departing from the scope of the disclosure.
Thus, the disclosure is not limited to the examples and designs
described herein, but is to be accorded the broadest scope
consistent with the principles and novel features disclosed
herein.
* * * * *
References